trad-
I think that 90% started off the same way. And most of us had the same worries. And I still have a number of pieces left over from my first rifle "kit".
Ask yourself a few questions-
1. Are you building a kit to save money? If you count your time for free, then you may save a couple of bucks. A really cheap kit may cost you more in aspirin than the rifle will be worth !!!!
2. Are you patient, and have a nominal ability with tools? Then you might enjoy the experience.
Remember, it will take you at least twice as long as you think it will.
3. Do you have a place to build this thing where no one else will mess it up, or you won't be messing their stuff up? first rifle I started, and the first rifle I completed were built on a Work-Mate bench in the corner of the livingroom of the apartment, but that wasn't the best of situations. Just ask my wife! ::
Buy the best parts that you can afford. If you want a simple percussion build that will produce a fine rifle, look at th Lyman GPR. If you want a bit more challenge, then contact on of the vendors like Track Of the Wolf. You will have more work to do, but that is the challege.
Good Luck!