A LOT of time. And that's if you're doing it half heartedly (cheap animation still isn't fast :I). I mean, I guess cheats exist but would you believe it if I said that I've never learned how to do any of them (background tweens nonwithstanding)?
But really, though, I like that animation you have. It seems like a clean up pass, because it's too smooth to be the 1st or 2nd draft. Looks like its mostly made up of keys and extremes, though, but I don't think you're aiming for little more than a skill test. I still like how he just zooms off into the distance. NOW I'm inspired. I can't get off my butt to draw anything, but animation is still my forte, whether I like it or not. XD;
One of the many reasons I found out I didn't like animation as a career, it happens, but it's either rare or not too many people admit it. There was plenty of other factors, don't get me wrong, but you know it's over when you finally get a chance to work on something that you think is really really cool, really fun and has a style you love, but reached the absolute bottom of the drive to care anymore. Fortunately...
For me, that is fun. I think if you got into it, you wouldn't get tired of it unlike animation which may burn you out if you don't live and breath it daily, and it has some pretty achievable milestones that people I've worked with seem to feel really good about. Even scenery design is fun every now and again, but maybe it's just me. Something to keep in mind, though, but I know different people have different tastes and ideas where to utilize their art. I'm speaking from work experience, but it's still only one man's point of view.
Well, you're certainly better than were I was when I was seventeen. My art was still very crude. In fact, you're better than me now. At your age, you've got a leg up on a lot of people who are seriously considering doing this professionally, I'd say that's quite a compliment. :D
Okay, I won't derail your gallery anymore. Anything else I'll take to a visitor message or something. D: