If you're gonna take classes, do it now. A martial art could come in useful but the training is oriented differently.
Understand that when you're fighting to defend yourself, nastiness is best.
Your instruction in self defense should address getting around the body's automatic defense system. Each and every one of us has had something from somewhere fly at us towards the face. Maybe a pebble from a mower ricocheting off the house, an errant bug, a spatter of grease from the stove. You flinch and it grazes your cheek or forehead, and you think to yourself "wow that was close"
There are zones on the body which are extremely vulnerable to injury but our nervous system has adapted to protect just as adeptly. Every try to kick a guy in the crotch? you just can't suddenly do it. The reaction times for the male body to thrust the hips back and bring hte knees together exceeds neurosyaptic control speeds, the same as something coming at our eyes.
The easiest way to bypass these defense systems is to overwhelm the attacker's nervous system with information. Multiple movements that are chaotic and and simultaneous. If your standing go for a knee to their crotch, the heel of your right palm upward into their nose and your left going for a jab to their neck.
When going for their jewels don't come up between their legs. you'll only get stuck and put in a compromising center of balance. Move your body towards theirs and bring the knee in to their shit from straight on. Thinking about it seems illogical until you realize the defense system is designed for them to pull their hips back and close the legs, bringing your body foward will compensate for that backwards motion and put you right in the home run range.
Practice the heel palm strike. If you don't know how to punch you can seriously fuck up your wrist and won't cause much damage because of flexing in the wrist. Hold your hand out in front of you like a limp Nelly with the fingers and wrist loose (go ahead, do it). Quickly pull your wrist back. Notice your wrist forms close to a 90 degree angle and your fingers are still loose. This is the proper hold. draw your elbow down to your side but enough room to fit your other fist between the elbow and your side. With your hand neutral and your elbow already bent flip your wrist back and thrust the heel of your palm up to eye level quickly and firmly. This strike in connection with the groin lunge puts either their nose or chin directly into the path of your palm. Hit the chin and you'll shatter teeth, possibly break their jaw bite off their tongue, and if your lucky knock them the fuck out or cause them a whole heck of a lot of neck pain real fast. If your hit their nose it'll break. if you stroke their nose with enough break force you'll drive bone into the brain and potentially kill them.