What type of board do i buy now?

Whats up guys quick background story. I live in south san diego where the waves are typically 1-3 feet somtimes 4 depending on the beach. Out the back on good days are usually 3 ft. Anyways my grandpa always had this old school encinitas shortboard lots of volume very thick, 5"10 board. I only started surfing about 3 months ago and was able to stand my first try with some other begginer friends. I have skated all my life and just quit a few years ago, im 17 so this makes the standing up part of the surf really easily. Anyways, with this old encinitas board as a begginer, i am only able to surf directly toward the beach and just started catching open faced waves at about neck height. I have only surfed down the line a couple of times however have an easy time turning and stuff due to my past skating experience.
So as a fast learner i went out to go buy a used board the other day when this guy at the store approchaed me very kindly and helped me out with tips of buying a board. I had my mind on a thinner longer shortboard just because my board right now is really old and needs minor repairs. However the guy told me i really shouldnt buy a thin surfboard for several reasons and when i look back it kind of makes sense because the surf here is only 1-5 ft at the highest on normal days and plus, i didnt realize how much harder thinner boards are.
With this in mind i dont know what type of board i should go for. With a surf like san diego, on average everyday conditions, would a 6ft thinner type short board just not be any fun for me? I learned extremley fast on my thick encinitas but still havent managed surfing the back, (usually just get crushed or ride it out on my belly) however i know within no time i will be able to ride out the back and go down the line.
I am not againts longboards either and open to trying to them, but i feel as a fast learner that a longboard would even be harder to control and manuever in the back because of how heavy it is. Also ive tried longboards of my friends at about chest high and that is a blast but i know it will get old and will lead me to wanting to surf in the back.
Fishboard?
Funboard?
Whats the best for san diego conditions year round for somone who is going to learn fast?
So as a fast learner i went out to go buy a used board the other day when this guy at the store approchaed me very kindly and helped me out with tips of buying a board. I had my mind on a thinner longer shortboard just because my board right now is really old and needs minor repairs. However the guy told me i really shouldnt buy a thin surfboard for several reasons and when i look back it kind of makes sense because the surf here is only 1-5 ft at the highest on normal days and plus, i didnt realize how much harder thinner boards are.
With this in mind i dont know what type of board i should go for. With a surf like san diego, on average everyday conditions, would a 6ft thinner type short board just not be any fun for me? I learned extremley fast on my thick encinitas but still havent managed surfing the back, (usually just get crushed or ride it out on my belly) however i know within no time i will be able to ride out the back and go down the line.
I am not againts longboards either and open to trying to them, but i feel as a fast learner that a longboard would even be harder to control and manuever in the back because of how heavy it is. Also ive tried longboards of my friends at about chest high and that is a blast but i know it will get old and will lead me to wanting to surf in the back.
Fishboard?
Funboard?
Whats the best for san diego conditions year round for somone who is going to learn fast?