Welcome Tim.
I have noticed you on another site, and that is no bad thing, the more sites you look around, the more you learn, or the more confused you get.
There is absolutely nothing wrong in being a newbie, we all had to start somewhere (well most of us have, others seem to think they came out of the womb with a vernier in their hands, ready to go, but they have a bad habit of trying to walk on water, and finding that they sink), and that is where we come in. Giving you the help, support and sometimes the correct directions to go in.
You are going about it the right way, getting the required info, chewing it over and then making your decisions.
If it was me, I personally would make a simple engine to start with, say an easy wobbler that will only take a few days to make. If you have no problems with that, not only does it give you confidence to go for a more complex project, but it gives the instant 'feel good' factor that we all crave for. From then on it gets serious, and you are hooked.
One thing we can't teach you is having a sense of humour. You will need a lot of that, we on here have a real wicked streak, and will extract the urine as much as we can.
Bogs