cut me pie:
I completely understand where you’re coming from. Most teachers and parents nowadays are not capable of answering questions on basics of Judiasm, and it is a really sad fact.
However, I know Rabbis from Aish that are ready and willing to answer questions like those. Asking them “how do I know there is a G-d?” is a perfectly acceptable question to them. These Rabbis are amazing. If you want to contact me thru YWN, I can get you a few names and email addresses and I think it might be very helpful to you.
Just remember: There is NO question that you are not allowed to ask. Every question is OK. You just need the right people to ask them to.