Had three concussions, all of them wearing a helmet (without my scull would have been mash), none of them from snowboarding. One of them was when I was doing a programmer training. Hit a tree (horseriding
) with the head and then the ground, again head first - I was told. No memory of it and the next day. "Woke up" in hospital and didnt know what year/season it was. For two weeks I was barely able to follow a soap opera. Going back to my coding two weeks later I wasn't able to understand my own notes. This was was very scary! So I understand your concern. Recovered from this one and the less severe others and still had enough spare braincells left to do a master and phd...
Add ruptured ligaments and spinal discs, broken feet and ribs, dislocated joints, 4 times in E.A. 20 years ago, my parents bared me to ride horses. 10 years ago husband wanted me to quit. I never did cause it's part of my life. Period. Eventually, all of them accepted it. Hubby now accompanies me to eventings to "be there to scratch you off the trees" as he says with a wink.
If you want to give up something you love is your personal decision. You're old enough. If it's your passion, stand up for it; parents/friends should/will understand, eventually. If it's your priority to do them the favor to quit, then quit. If you gain more with loosing the scare to be injured than you loose by quitting during your study, then quit.