I have to agree with Old man surfer 100%.
If you can get in the water daily and you REALLY want to learn to surf and rip a wave then by all means get yourself a shortboard. I surfed logs twice before getting my own board and even that was pretty short for a first board (I am 5"5 first board was 6"3).
I had fun on it in typhoon swell over in Hong Kong but ended up going ot australia (originally for 3 weeks, ended up there for 9 weeks and doing 3/4 of the east coast) and ended up buying myself a 5"9 shorty.
I did not catch anything for at least 2 weeks, not down to the fact I did have the skill but because I did not have the strength required to get the board going not only that regardless of how much i "thought I knew" the shortboard showed me that I was still an absolute beginner.
9 weeks later and I feel i came away an intermediate surfer, having been on a variety of breaks / conditions at all tide levels, Able to pull off a decent bottom turn but now making that transition to bottom to top surfing - in my last week there, the 2-5ft swell that was rolling through left me wanting it to get bigger.
The sweet and curly;
If you can surf daily, have pure passion and drive to surf as well as the willingness to change your life style - Get a short board, but be warned its not easy and much more then just paddling every day - Sleep, Eat well, Excercise & Passion will get you far.
Good luck

Its just you and the heart beat of the earth, that moment when u take the drop nothing else matters your mind is completely free of all material thought processes. Your human.