Welcome! I started riding at 17 and I’m still riding at 26 now. I have only had 2 skis and the first one lasted me 6 years of surf abuse. My advice: Ride that ski, learn the basics of riding in the surf, maintenance, and make mistakes on it while you save for a fairly newer 701 superjet. Once you have the newer 701 superjet, you will be more experienced to start building it correctly with aftermarket parts and you will be set from there to do whatever you want with it.
For now: Ride, always flush/rinse the ski after saltwater, and buy a service manual for your ski to start learning some of the maintenance and upkeep. Also, this forum has infinite information as well as misinformation all over, so good luck haha.