SO, I really want to make a sweater but I am super scared that I will screw it up somehow, and I found a cute poncho pattern, should i maybe start with a poncho?
If you want to start with a poncho, sure, go for it. If you want to do a sweater, what kind do you want? Pullover or cardigan? A top down raglan worked in one piece is a good start IMO.
Well, i found a pattern for a pullover that I liked, in a book from the library . it kinda looked like a hoodie.
What is the name of the book, and the pattern?
The Yarn Girls Guide to simple Knits…idk what that pattern is named though 
Its a really cool book though
I believe this may be the pattern, 'Not Your Standard Issue Sweatshirt.
Are you a member of ravelry? It can be a very valuable resourch and you will certainly want to join if you are not; many members of KH are members of ravelry as well. For this pattern in particular, you can read raveler’s comments and find out what type of yarn they used, etc.
I agree with the feeling of the other posters. If you really want to make a sweater, then that’s the thing to do. (I’m not sure a poncho is going to be all that helpful as practice unless you’d like to make one.)
We’ll be happy to help you at any step along the way.
I’ve used the Yarn Girl’s books before and their instructions are super simple & helpful. In fact, my very first sweater came from that book (one of the cardigans) and everything was spelled out for me!!
I’d say start out with a sweater and see how it goes!
knitcindy
Make your sweater. Cindy vouched for the source being excellent. I started with a sweater that wasn’t geared toward a novice and thanks to everyone here I still got it done. Just take it one step at a time and ask about anything you aren’t sure of. You can do it.