Hi
@dst87 you've received lots of good and postive advice which I can only echo - from experience around 5 years ago I "inherited" a mountain bike and thought I doing brilliant if I did 5 miles round our estate! I used to ride on cycle tracks locally but got fed up having to avoid dogs, kids, prams, horses, bricks - and neds throwing bricks, dogs, prams, horses, etc so decided the road was safer. A road bike naturally followed, then another, then another... (all essential and serving different purposes, obviously
) I'll now quite happily ride 100k on a weekend morning, so it CAN be done!
Couple of things: if you are on Weight Watchers ensure than you are getting enough carbs for the upturn in exercise -
nothing worse than a "bonk" on the bike (not what you think it is, look it up)
whatever bike you choose you will soon be coveting another, for an entirely different purpose (going uphill, going downhill, going faster, going lumpier, etc etc) so expect that whatever you choose now may not suit you in a years' time - that's ok, you're into N+1 territory (look that up too...)
Oh and when you get your new bike and see how shiny it is you'll want to take it to bed with you and you'll be horrified for ever thinking you could leave it in the garden.
Ok that was 3 things so I'll shut up now! All the best, hopefully see you on a ride sometime. Cheers, Mark