Self-defense law is different in every state, so you may want to do some research. In Washington state, you can use physical self-defense if you have a “reasonable” person’s fear of imminent physical harm.
After you learn and practice your strikes to decisive and good pain targets, you will put them together into combos of 3 or more techniques. Your 3+ combo strikes have to follow each other in quick succession — BAM BAM BAM . . . — for maximum effectiveness.
The good news is that most stranger and acquaintance attackers are looking for victims — women who are more likely to be easily intimidated and scared into silence. If you recognize that you need to fight — and do fight back — there’s a really good chance the attacker will back off and find an easier target.
But the most essential reason to learn physical self-defense is for that confidence that you have a back-up plan. When you have that confidence, your posture, eye contact, and voice will show it, your body language will be more assertive, and you are less likely to be selected by a potential attacker as a target. And less likely to have to use physical self-defense.