Remember that you're there for you. It's not gym class. Now, since every box is different, I don't know what kind of atmosphere you're going to run into, but I've been to a bunch of other boxes plus my home box and all of them have been very open and supportive. Remember, we're all adults now, they're not the sillyness of teasing and making fun that shows up in gym class. If someone is having trouble with something, everyone tries to help rather than make them feel bad. At least from what I've seen everyone wants everyone else to succeed; in high school, gym class is a zero-sum game, you only feel better if you put everyone else around you down. In real life, people want you to better yourself, and crossfit is a good place to do that (assuming you have a good box to train at).

The hardest part of crossfit: Don't be afraid to push yourself, but also make sure you know your body and don't get injured.

Take it one WOD at a time. In the beginning, take pride on completing the WOD, celebrate every small victory. One more sit-up, one more pull-up (who cares if you need bands, they still count), one more box jump before time is up. This will give you a feeling of accomplishment. You will be competing against previous score instead of another person.

I hope my short story will help you a little bit. I walked into a crossfit for the first time 2 years ago. I was severely overweight, and I had been existing, not living, with permanent nerve damage throughout my body because of a car accident that occurred 10 years earlier. I didn't know how much I would be able to do but I needed something to help me cope with the death of my mother. I started out going 2 days per week, and I was doing it for my mom, not me, because she had always worried about my health. At some point, I don't know when, the WODs were for me, I wanted to improve for me. It wasn't overnight and it wasn't easy but it helped me reclaim my life, and my self-confidence. Thus far, I've gone from a size 20 to a size 10 and I'm still reshaping my body. I am healthy, and happy and the damaged nerves, that plagued me for 10+ years, are protected by copious amounts of muscle which has alleviated my pain.

I still have bad days, when I'm struggling with burpees and they seem like a cake walk to everyone else, it's only natural. Now, I can appreciate how much I've achieved and take pride in that. (Most of the time.)

Crossfit is a journey, not a destination. You improve every day just by completing the WOD.

Best of Luck. You're stronger than you think you are. You can do this.

Embarrassing? No one is judging you. Every single person there started somewhere…remember that. You're going to progress so fast and you'll be the support for the next new person with the same insecurities.

Don't go overboard at first…be sure your coach is scaling for you and don't over do it or you will hate it and not want to go back…but if you start slow and commit to 2-3 months, I promise you're going to love it and the fast changes you'll see in your body. For those with body image issues, Crossfit emphasizes strength and not appearance…so it's a healthy way of thinking. Hang in and let us know how you're doing in a couple of weeks.

Just know that you're making yourself stronger with every time you complete a workout. The whole goal is to better yourself, not meet anyone else's standards. Strive to be better today than you were yesterday and you'll be amazing.

No need to feel embarrassed. Everyone starts somewhere. Paleo parents just did a great post on being content with who you are and not trying to fit the "super image" that paleo puts forth as the typical.

I was a slim distance runner when I started up with xfit, and it does take some doing-I can empathize. As a 40+ participant who was never especially coordinated, it can be a little demoralizing sometimes when I get caught up in competitiveness. But here's the deal--this is not your job. You do this to make your body feel healthy, to make some nice new friends, and to have some fun. It's not a race, and it's actually a gift you're giving to yourself.

It's super easy to get caught up in the imagined competition, but you've gotten some wise advice here. Listen to your own body, and enjoy the excitement of stretching your limits (within reason), but scale when you need to, rest when you need to, and know that all good things take a little time.

I've made some terrific friends, and I've achieved some athletic goals that I'm really proud about, and even though I've had to inch my way up, even the tortoise finds the finish line!

You can do it!

I can relate to how you're feeling. Last fall I had a series of minor, but annoying illnesses piled up one after the other. It knocked me out of any kind of workout routine and I started gaining weight. It stopped me from doing activities I had previously really loved for fear of being the slowest, most out of shape, etc. In February I just told myself that I had to get over it and do something, so I went to Crossfit. I started, like you, with one-on-one sessions with a trainer. My box offers the option of a group intro session, but I wanted the privacy of one-on-one because I had a feeling I was going to suck big time. The first two sessions were particularly terrible because every movement was hindered by self-consciousness. But my trainer was (is) super encouraging and by the third session I was completely addicted. I still see my trainer privately twice a week and go to group classes two or three times a week. There's no judgment, no feeling of inadequacy when I have to scale a WOD. That inclusiveness and understanding seems to permeate throughout the CF Community. Stick with it. It's worth it.

And one more thing that's helped me....I always check the WOD online and youtube any movement in the WOD that is either unfamiliar or I know I'm not so good at. Even if I know that I'll be doing something different with my trainer, it keeps me excited and helps me understand the nuances of various movements.