have a read of this to see the usefulness of skating to surfing - if Elissa Steamer found it hard to surf, you may also find it not as easy as you think.
http://www.surfermag.com/blogs/culture/ ... ed-a-kook/However, as a 13 yr old 115lbs, regardless of whether you are a skater or not, you can probably start off with a 'shortboard'. Whether 6ft2 is a good choice will depend on width and thickness and outline as well; probably something more 6ft6 and slightly wider than a high performance board (meaning around 20inches) is a reasonable starting board (on the assumption you truly will be surfing 8 hours a week)
That said, you may want to, if you can, get a longer board (7ft+) to learn the basics and then switch down to a short board in a few months