Hi there, Everglow, and welcome to Scarleteen.
I'm glad you were able to ask us all these questions about your labia, and don't worry; we're here to answer questions that feel scary or silly and certainly won't laugh at any of them.
There's a pretty wide variation in how large/long someone's labia might be, so even if yours feel "large" to you, that doesn't make them abnormal, weird, or unattractive in any way. There isn't anything you can do to keep them growing, the same way you can't keep yourself from getting taller; we can't know if they'll see any more growth or changes or not, but it isn't something you can impact yourself.
If you're having pain when riding a bike, you may have luck tucking your inner labia inside your outer labia when you put on your underwear or biking gear; that's not an uncommon thing for people to have to figure out how to do if they have inner labia that ever hang past the outer ones. (Again, this is super normal and not weird for labia to do!)
We actually have a bunch of information on inner labia, the idea that they can be too long/large, and all the questions that come with that worry, here: Give'em Some Lip: Labia That Clearly Ain't Minor
. I think reading through that might set your mind at ease some; we can certainly talk about further questions or concerns you have after reading through it, but I hope it'll clear some of this up for you!