jr, thats great to hear!
I wrestled in h.s and did jiu-jitsu not too long ago and ended up leaving cuz of school & being a broke *ss. I was about 2-3 months prior to starting prep for a blue belt test. (only 5 belts in JJ: white-blue-purple-brown-black) I am now concentrating on getting in shape to go back (not that its necessary)
I too liked the submissions aspect of mma but make sure you're ok with sport jiu-jitsu (wearing a gi) its vastly different than no-gi. About half the techniques are lost when not wearing the gi. I hated it at 1st cuz it neutralized half the wrestling background I had, the other was gone cuz we'd spar starting on the knees. I was taking down blue-belts all the time (literally double-leg pickups) on the rare occasion we started on the feet or did no-gi. It doesn't make sense but it was kind of a trip to nearly rag-doll other fellow jj newbs who were black-belts in tma (Karate, tae Kwon do) w/ only h.s wrestling.
some general tips:
-work on your flexibility; it can be done anytime time - sittin watching tv, get a stretch in before sitting down & leaving lecture etc.
-drill techniques your weak side (non-preferred side) make it strong. I found I was a righty for sweeps (I sweep to the right) & I pass (guard) to the left. I've found that after being shown a technique, 1st drilling it on my weak side helps me dissect it/break it down step-by-step and commit it to memory better than using my strong, natural side 1st.
-have fun when sparring but think EVERY time:
-What are my tendencies?
-Why specifically am I susceptible to this/that: armbar/triangle/sweep?
-If/when you develop a go-to move, dissect WHY its your specialty & how to apply that process elsewhere.
-a beginner tip: to help you get thinking about how its a chess match - if you want to pull opponent's arm in, then push it out at first, then use his natural reaction of opposing you (by him pushing back) to aid what you really wanted. My first big reversal I rolled over a guy 1.5x my size from side-mount position cuz he "helped" me so much.