Hello Jalyha, I hope I'm able to answer a few of your questions!
You were exactly right behind the reasoning of why reputation
power isn't given to brand-new folks. The idea is that you have
to earn some rep before you can contribute back.
If you rep another user, but you don't have rep power yourself,
they'll generally appreciate it anyway; most of the members
here will be more excited someone liked what they did. Rep
isn't a very competitive thing. So no need to feel like you should
go back and do it over again when you get rep power.
You probably should use the like button more than repping,
as I think it's a more general expression of approval. Rep is
normally reserved for posts including maps, whereas a like
might go towards a useful comment. Plus, a like shows up
on the member's profile whether you have rep power or
Keep working hard and posting maps to earn rep; another
good way is to complete a map for a mapping challenge.
Voters sometimes rep the artist who had a map they liked.
These are obviously just general guidelines, as the technical
rules and stuff were posted at the start of the thread. It
didn't seem like you had any problems with that. Plus, I'm
not a knowledgeable member of the community yet. Just
what I've observed.