To be honest (that's what you're looking for, right?) you can do anything you want if you're willing to sacrifice a little, and dedicate yourself to it.
If you have a place to keep the engine, and tools, and parts, and supplies, etc..., I'd say to go for it. Get an engine stand, a workbench, engine manuals, LOTS of coffee, and go for it.
Every hotrodder here who has built up an engine has had a first time. And 17 isn't all that young, comparitively speaking. I tore down my first engine, with a buddy, when I was 16. I worked my butt off for parts/tool money, and it took about a year to do, but I/we did it. My father was so impressed with my dedication, not to mention the improvement in my Math grades, that he slipped me a few extra bucks on the side here and there, or bought a tool he really didn't need, then let me borrow it. (C'mon Pop, how many piston ring compressors do you use in a lifetime?)
If money is a major concern, however, I'd wait a while. The old saying, "Speed costs money, son... How fast do you want to go?" is dead honest. Yes, you can do things a little at a time, but sometimes a project done that way takes on a life of it's own. It becomes akin to the Chinese water torture - it just never seems to end.
You have to decide how bad you want to do it. You have to decide if you have the time, money, and resources needed to complete the project. (The $5000 estimate given earlier is a good estimate, depending on what you're building.) You have to decide if "now" is the best time to start on it. Garages and back yards are full of projects started, but never completed. You have to decide if you have the dedication required to take on a project of this scope while you're still doing everything else in life that you're doing. I don't think your age has anything to do with it. Maturity damned sure does.
Waiting isn't a bad thing either. I'm 42 and am just beginning my first frame-off rebuild of a '54 GMC Panel Van. The time is right for me. You have to decide if the time is right for you.
Good luck with whatever you decide.