1.upper body and core strength will help your cycling way more than any potential negative from weight gain- you are not going for schwarzeneggar here, you know.
2. squats are great exercise for building leg strength. if you can ride, ride, but unless you live where there is no winter there will be times to do other things, such as lift.
3. proven fact that cycling is basically a non weight bearing exercise and people who exclusively cycle have a higher risk of fractures.
4. 16 yo dudes don't "get" hernias from lifting- hernia in a 16yo is almost always something they were born with.
5. have fun
6. everyone who is anyone over at the ocp lounge knows the quickest way to get faster- NEW BIKE!!!!!