Hi Kerry,
I too have rediscovered cycling after many years. I have fallen in love with it too. Interestingly, I too have lost a bunch of weight going from about 215 to 115. I am 5' 2". I have found that the cyling toned my legs and rear end quite a bit, but gravity is still winning in the tummy area. I try to do crunches but they are sooo boring compared to being on the bike. Anyway, welcome and have fun. In addition to a beginner course, I would suggest if you have a friend or someone who can show you how to change a tire that you practice it at home a couple of times. I did that with my SO and it helped a lot.
- Pata