Initially most of the skills, sports and subjects have very fast learning curves. You learn a lot in a short amount of time, and every hour, every day brings you something new. Eventually, your "ROI" will decrease, and you'll have to dedicate more time to keep improving. At some point anything becomes a full time job.
So try what you want to try, set objectives, but consider how good you want to become. It's fine to remain an amateur, to stop and try something else. But if you ever decide to master anything, you'll want to invest weeks, months and years to do just one thing. Many other people did dedicate their entire lives to that subject/skill/sport. If you ever want to be as good as them, you'll have to match their effort.
Also remember that often it's not important how much you learn, but if you apply it in your life. You don't need to be a great athlete to enjoy biking. Sometimes all you need is get a bike and get outside.