Hmm, limiting your lifestyle???
Nope, can't say I've noticed Jim (my boyfriend, has a mechanical aortic valve) doing anything to limit his lifestyle. He mountain bikes, rides motorbikes, tries to surf (actually, we haven't been since his op but only because we haven't been anywhere with decent waves), uses grinders, drills, chainsaws, etc. His friend's jetski is currently out of action and I personally think they're a bit dangerous, but I'm sure that wouldn't stop Jim going on it again.
Having said all that, it's still early days for you. It can take a year to feel fully "normal" again, sometimes even more. I think it's perhaps even harder for people in their late 20s than possibly any other age - you think you're at the peak of physical fitness, over the hard partying of college and ready to make long-term plans for your future, when WHAM! you find yourself on a hospital bed on your way to open heart surgery. Not what you'd been planning at all...
Give yourself time. Maybe try going on a nice quiet road on your bike, get used to handling it again, wear a helmet (but so should everyone) and enjoy the feel of the wind on your face. But under no circumstances should you be giving up the things you enjoy.
Gemma.