Bought a new board, now comes the newbie questions!

Just picked up my new/used board this past weekend and have a newbie question. The board is a Ricky Carroll Performance Longboard 8'10" (17.5x22x13.75). Both my wife and I went out to surf afterwards, which mostly consisted of us making a spectacular demonstration of 'How to Wipeout 101'. But we had a lot of fun doing it and definitely got our exercise. While we took some lessons that previous weekend I definitely need to re-visit the basics and practice some things before our next outing. Also, I'm almost 6'2" and 170lbs so I believe this board would be considered more of a mini-mal for me? I wanted something that I could have fun with the more I progressed with my surfing abilities, although it may be harder for me to learn on with smaller waves. Thoughts?
So now for the newbie questions! The board came with four sidebites and a central 7" fin (Wingnut Cutaway). I removed 2 of the sidebites and kept the single longer fin per recomendations of the surf shop. Is a 7" fin long enough? I'm not sure if I would be able to tell the difference anyways, but I've read that a good general rule is one inch of fin per one foot of board. Just want to start off on the correct path if I need to change something up now. Plus, as my wife would point out it would give me one less thing to blame (it was the fin's fault!!).
Thanks so much for any input. Great site too, have been reading everything I can since I was struck down with this surfing affliction. Wish I had started this journey earlier in life (32 now).
So now for the newbie questions! The board came with four sidebites and a central 7" fin (Wingnut Cutaway). I removed 2 of the sidebites and kept the single longer fin per recomendations of the surf shop. Is a 7" fin long enough? I'm not sure if I would be able to tell the difference anyways, but I've read that a good general rule is one inch of fin per one foot of board. Just want to start off on the correct path if I need to change something up now. Plus, as my wife would point out it would give me one less thing to blame (it was the fin's fault!!).
Thanks so much for any input. Great site too, have been reading everything I can since I was struck down with this surfing affliction. Wish I had started this journey earlier in life (32 now).