My parents keep telling me not to overdo it and similar warnings, but I brush that off since my own family's never actually dealt with their own weight-related health issues, so why would their opinion carry any weight here?
On the loose skin front, the advice I keep seeing most is that staying at a stable weight helps the most, I've got sagging spots from my own loss and surgery just isn't something I'm considering. That said, hitting the gym and lifting heavy adds muscle underneath, giving the skin something more to sit on.
Good luck, you've got this, you did this for yourself, now it's about learning to embrace who you've become, anyone who has a problem with that can move along.