It does get easier - especially if you ride and train with the same people for some time. You will get to know and trust them. You will also be able to start to read the body language of the riders that are around you even if you do not know them. After some time you'll start to be able to read the pack dynamics better and to know who you should be able to trust and who you should stay away from.

I admire that you admit that you need to build your pack skills. We definitely have some gals out here that could use some of that. To be completely frank riders in your situation can be a bit scary for everyone else- strong enough to be in the pack, but without the pack handling skills to be safe, so its really cool that you want to learn. Often new riders can be somewhat hostile to advice, but if a more experienced rider gives speaks to you, they usually are doing it to save you and themselves some skin, not to just be critical so its good to listen.

Of course, riding in a group is the best way to get better, so it sounds like you are on your way. If you have any training races in your area they are great too. Skills clinics that have you practice cornering and bumping are useful as well. Better to experience some of these things in a controlled situation before you experience them in the real world. If you have the opportunity to join a club or better yet, a team, do it. The support and advice of others who have already been where you are at now is great. In any case I think that it is normal to be at least a little nervous in a pack and maybe even good. You definitely need to pay attention at all times so relaxing too much might be detrimental.

Don't worry - everyone is a little nervous, but it keeps us on our toes. You'll get more comfortable as you do more group riding and, at least for me, its never as scary as I think it will be. I did my first crit last weekend and I've always heard about how bad they can be. I am happy to report that it was not as nearly as frightenting as I expected. I went early, rode the course with some of the higher catagory women, got a lot of great advice on how to corner in a crit and did fine. With your background in mt. biking you are proabably a pretty good bike handler and you should do fine with a little practice.

Good luck and keep us updated on how you are doing.