HMS_Dave
Grand Old Lady
I started cycling at 25 stone and hadn't cycled for some 20 years. I could barely get down the road and back without my thighs begging for mercy and my lungs burning. You have to take it easy and i imagine that must be difficult with confident cyclists around you but with patience and proper support from them you will find that you improve in pretty much all areas quite quickly after the initial aches and pains from the saddle, legs, shoulders, back etc... The last thing you want to do is injure yourself so don't push yourself early on, jump on and ride is all for now. If you feel confident at dusk or dawn then fine, but don't let others put you off, you are well within your rights to cycle whenever you want.
Good Luck
Good Luck