Hello! And welcome to the wonderful world of crochet.
I will try to help as best I can!
1. It's hard to see what you mean by crooked edges, but if the pattern calls for a certain number of stitches, you should have them. I have a guess on what you are doing wrong, and it's probably the same error I kept making when I was a newbie. The initial turning chain most often counts as a stitch. When you are working back across the next row, don't forget that your last stitch will be INTO that turning chain. It's a little awkward when you are first starting out, but it will get easier over time.
2. As for your granny problem, that's a little hard to tell where the problem lies without seeing a pic. Post that one again when you are allowed to show pics.
3. Frogging means you've made too many mistakes in your work and you have to "rip-it" out. Say "rip-it" a few times to yourself and you will see where the term frogging came from.
4. For yarn weights and terminology, might I suggest www.craftyarncounci l.com
? It's very helpful in so many ways!
5. That afghan is beautiful! As a beginner, I think you may want to work on some other techniques before tackling this. I only say that because it looks pretty intricate, and I don't want you to become discouraged at this early stage. Think of a pattern like that as a reward for a lot of hard work.
I hope some of this info helped!