Maybe don't build a whole tail kit, but look over the sub assemblies you get in your purchase; see if there are a couple pieces with blemishes and then build them over, maybe you'll do better, choose between yours and the original, either way, you learn. Just look at the plans/parts list and order what you need.
If the HS does not have the service bulletin modification done, I would suggest rebuilding it from scratch. That way you get the practice and can incorporate the mod as you build rather than tearing the current one apart. The HS is a little tricky with the new doublers. Be careful, do your research here and on builder's sites, ask questions. Every time you drill a hole make sure you have proper edge distance on every part. Edit: Just noticed in your signature looks like you're going to be building a 10 so this tail mod probably doesn't apply for that model.
The wings are easier than the tail, but more expensive in money and time if you screw up.
As far as learning to rivet - you can do that with scrap pieces. I would recommend learning to buck with an experienced person on the gun and how to run the gun with an experienced bucker, before you try to do both at the same time or team up with an inexperienced person on either end.