Awesome. I recommend researching! It will save money, time, and headaches. For example, when I started out I had a 10 gallon tank and when I went to the fish store I would pick out an appealing fish (I was kind of young too so didn't think of researching fish when I was about 10). I would buy fish that I later found out were not compatible and picked on each other, or needed a larger aquarium than I had. Through the years I got so many different fish, and changed the design numerous times that I wish I started off researching! Personally I love a natural look w/ live plants and manzanita or driftwood, but starting off with decorations and gravel is fine.
Terrariums normally have thinner glass b/c they aren't made to hold water. I recommend leak testing it first before anything.
The articles on AA would help w/ providing basic knowledge of setting up a FW
tank. Good luck!