Hi Ladies. I'm going to make my first full lace purchase and I'm a little nervous!

I have been reading the newbie threads and using my search function to try to save you ladies from repeating this thread. So I searched for threads on cap measurements and construction and found two. From what I understand if you are worried about your measurements being a little off you can order a stretch cap which is from ear to ear.. or a stretch cap that is in the middle. So my question is which is better and how do these two types differ? Also when I did some of my measurements I came up with like 22.5, 14, 11, and 11 I think and I'm still going to measure some more. I am worried if I am doing it correctly. For measuring your hairline do you measure from side burn all the way over to the other side burn? I want the lace to cover both my sideburns. But I have heard some instructions just refer to measuring to the ears. So confused about this!! Also do my measurements so far sound strange or like I'm totally off. I'm so nervous .. I just don't want to mess this up!!!! Please help!!!