Welcome! I'm still shedding some of that winter "fluff". My best friend and outdoor buddy underwent gastric bypass surgery two years ago in February. She's shed over 100 lb and can do the outdoors stuff that was next to impossible for her before.
Hang in there!
As far as the backpacking and road biking goes, we were all newbies once! Plenty of experienced folks around here to get advice from. (I'm a relative backpcking newbie, having been away from it for 30-odd years, and just getting back in. What I know about road biking could be written on a postage stamp with a Magic Marker.)