I've been looking into autocross and have not the slightest clue where to look to find and enter an event
Figure out where you want to race at. Look at the track's calendar page and see what events are going on. Look up those companies that have rented the track. I'm sure you'll find a few. Auto cross is completely different than track racing. Try and find companies that do on track driver instruction. See if they'll let you bring your jetta. Most likely you'll be put in a group that at most allows point by passing on the straightaway. It takes many hours on the track to become proficient.
As far as Lemons goes, it's a process and you may not like a few things I'm going to tell you, but its just the reality of it:
1-Nobody is going to let you drive their car. The amount of time and money invested into our hunks of junk is far too great to give a novice driver the opportunity to ruin the car. My best driver ruined mine last race. Not his fault, but if it can happen to someone thousand+ hours of racing experience, it can happen to anyone.
2-Repost your ask to join a team. Instead of asking to be a driver, ask if you can crew for a team. Explain how you're strong and willing to carry gas jugs to the hot pits, run out for supplies from autozone if needed, pay for your portion of food, crew fee, etc. Explain why you're going to be an asset to the team. Be realistic, understanding how a car works is very different from being able to repair a car. If nobody wants to offer you a crew spot, ask if you can shadow a team. I learned a tremendous amount just shadowing a team.
3-Be Nice, Be friendly. This will go further than you can imagine.
4-Be patient. You've got 50+ years ahead of you to race. It's going to take time and money to get there.
Good luck. If you're ever in California, you're welcome to join my team as a crew member.