When you rivet, be sure there are clecos on either side of the rivet you're squeezing, if possible. You'll have less chance of the two parts having a space between them.
Just figured this one out a few days ago, use a heat gun for a few seconds and they will peal right off leaving no residue. If you leave the heat for too long it will still come off very easy but leave a little residue that MEK takes off with no problem. Congrats on the first rivet, only a few more to go till shes in the air.
I think you need to drill that rivet out and start with the rivets at the top of the picture...
I just put a few drops of mineral spirits on the stickers and let it soak in for a few seconds. They peel right off and drying with a paper towel removes any residue. Heat also works, on the powder-coated stuff. But it doesn't always seem to work as well on raw aluminum (pushrod tubes, etc.).
Congratulations! I just started myself a couple months ago. Great fun along with some occasional frustration. Just don't be afraid to ask even what you think might be a stupid question. If you're not sure, take some pictures and ask about it. This group is amazingly helpful and very easy on us newbies as you've discovered already. I've put up pictures with some question, got my answer within hours (or minutes) and then had comments related to things seen in the pictures that I didn't think of.
Moved on to the front HS spar last night. It's a good time. The #1 rule I've learned so far is - read the dang instructions and review the plans view often and read ahead a little to see what comes next. The instructions are not a do this, then do that. The next check might change how you do the one before it. Ask me how I know...