I have been to a few support group events. They were held in places where you could meet others under the big Transgender umbrella that includes crossdressers to post op transsexuals. They were social events, and many offered a place to change so that one could leave their house one way and then change at the venue into their preferred way. They always welcomed newcomers. Conversations were all over the place and if you ask, they will answer your questions. Most groups allow you to come in your normal mode to check the event out. My experiences are near San Francisco, California, a very, very accepting area for all of us.
If they have support groups where you are, even if they are a long drive away, they could be a great help to you. You meet new people similar to yourself, you get out of your house, almost into the real world, you can network with others to maybe find someone close to you to become friends. You are building courage and confidence with who you are and what you can accomplish. To join a support group, you will need to contact them. When you do ask them all the questions you have about how they operate, what are their rules, do they have a place to change clothes, can you go as your normal self the first time to check it all out, and any other questions that you have.
To find a support/social group just Google "Transgender (or "LGBT") support groups near (your city and country)". Also, tell us where you live and there may be someone from your area that can also help you out.
I understand where you are and also think that your idea of joining a group may be helpful for you. They can, because you will quickly see and meet other people like you and they are doing OK. That means that you can eventually do the same things as they do and feel more confident in who you are and what you can do and how to do it. I also like that you have considered or are considering therapy. If you can find a therapist with transgender care experience, they can really help you understand who you are and how to feel more comfortable with that and live your life.
So, please do not be afraid of joining a group if you can find one. Good luck,
Allie