Surfing Waves

Hello there! I'm Alexandre, I'm 17 and I'm from Portugal. So... I'm now starting surfing and I've seen several videos and read on various websites about what kind of board should I buy, but I'm still a bit confused about it... Yesterday I surfed for the first time. I went with a friend to the beach and rented some surfing gear. They gave us a wetsuit and one of those foam longboards, the size I think was 8'25". Because I had already seen some videos teaching how to surf, I knew something about how to paddle and pop up, so after a few attempts I was able to catch some waves, and I though it was pretty easy actually, but my friend didn't. He didn't catch any wave... Maybe because he didn't have balance or didn't know when to stop paddling or pop up... For me it was easier probably because I have been skating for a long time so... Yeah, I think it helps a lot! But well, I do not have the money to spend in a surf school, so I want to buy a board and a wetsuit and learn "by myself." And, although I found it easy, I found the board I've used a bit too heavy and too big. I measure 1.69m (5'54 ") and weight 60kg (135lbs) and I was thinking of buying a used 6'2" surfboard, but a hard one and not one of those foam ones. And I'd like to know what you guys think about it and if it is a good or bad idea. I was thinking about something like that board in the photo...

Ola Alexandre , just good back from Baleal on Wednesday, enjoyed myself thoroughly.
The board you are looking at is not entirely suitable for a beginner a little short it is more a board designed for a capable rider in mid range waves of good shape, you will struggle to catch as many waves as you need to,progress well!
Your age is an asset, so you can still go shorter that I might otherwise recommend.
Look at something no less than 7ft, with a fun board shape, it will give paddle mobility and you will progress well in skills learning.
You can do shorter but progress will be slower!