Hi Laura,
Welcome. I'm fairly new here myself. I am 51 and never sat on a bike before a few weeks ago. Like you though, I feel it is the exercise for me, it's just so freeing and fun isn't it? I have my fear of riding down hill (even little ones) at present (see nervous nelly scared of hills thread) but I am making good progress. Like you, I also have weight to lose (a couple of stone, 28bls for me to be happy with myself, I don't want to fight the fight to be slim any more!). Someone else in our age range (can't recall who) was saying she has lost 60bls since taking up cycling. That isn't why I started, but I'm loving the idea that it might have that effect