Surfing Waves

Hey,
I was wondering if anyone could pls help me out.

I am a beginner but I would really like to purchase a board that I can use to teach myself on.
I am 17 years old, 45kg, and 5'2.
I saw that to get a fish board (which is the one I am most keen on getting since I think I could improve most on it and do not have enough to buy a board, and then another board shortly after if I have improved) you need to be small light and okay in the water and I think I am those things.
I think a 32-35 liter fish board would be good? I think?
How tall do you think the board would need to be? Do you by any chance know any websites that sell cheap second hand boards?
Or is there a complete other board you would suggest?

Thanks SO MUCH!

"Beginner" can mean different things depending on the person and area you surf. So to help figure out which board to recommend:

1) Can you paddle into, Catch and Stand up on "Green waves" ? Meaning you are not being pushed by the white water or standing up on the sand and jumping onto your board.

2) What size board did you take your first lesson on ? Or have you not taking a lesson yet ?

But without knowing your answers, I always recommend to learn on a board 3 feet over your head, thus at least an 8'2". ( Costco Wavestorms softboards are 8'0" but have as much float as a 9'0" hard board, so those are okay and great to learn on ). After you can catch Green wave, Trim across the face and begin to try turn ups and turn downs, then move to a board 2 feet over your head, like a 7'2" funboard. After you've been doing cutback both front and backside, then you can venture into the big fish / hybrid 6'6" ranges.

You are not going to learn the proper way to surf on a FISH. ( unless you want to Surf Like a Pro in 25 Minutes )