I'm 27 and the same used to till I was 17/18 but then just lost interest. Its up to you personally people give it all the chat that you feel better, but if its not for you then it really makes no difference, I mean if anything I'm in a better place mentally now than I've ever been. Physically I'm still fine aswell managed a 10k for charity last year in 33 minutes with no training and that shut most my mates up.

I'd still advise not eating loads of junk and sitting about everyday, even going out for a walk 30 mins or so a day is probably enough to keep you healthy if you're not overweight already. Getting a dog is an easy way to get some motivation to go out if you need it.