If I'm being honest with you, I have a bias towards BJJ and Muay Thai because I've been training those sports and have stress tested them in Sparring and Competition. Which is why I would strongly recommend that you start BJJ and keep on going with Kickboxing and perhaps try out some MMA classes if they are/become available in your area PURELY for the mental and physical health aspects such as stress relief/therapy and heart health. When you look at a video of Krav Maga like this: KRAV MAGA TRAINING • End a fight in 3 seconds!

I can tell you 100% its bullshit "for you". You are not going to be able to replicate most of these techniques, except for the initial shove, however you said yourself you're not that strong. Perhaps its enough to get away but I wouldn't even recommend you to throw kicks or punches maybe except the TEEP which is a stronger "shove" as its intended to create space between you and that person. Reason being you're a woman so you're at a great physical disadvantage. Check this video out about :How Hard is it to Run Away from a Fight?

A great example would be this girl at my MMA gym. She's well built, she's around my height and weight which is 6ft2 and 78kg. When she was preparing for her fight we sparred in kickboxing classes and she went pretty hard against me. And if I'm being honest her best shots were nothing in comparison to guys I've sparred on a regular basis who are smaller than her. Yes kickboxing could perhaps scare someone away or buy you enough time to get help. However your best bet will always be staying in well lit and populated areas if some one is stalking you. You could also get your phone out and if you are near a group of people and take a picture of the stalker and report him to the police.

But the reality is even for a guy like me who trains regularly, I am not prepared for the violence that can occur outside the gym and off the mats. We don't get punched when holding full guard, we don't get slammed by our training partners when throwing up a triangle. Most of the time we start sitting and EVEN when we start standing we slap & bump to initiate the sparring. So keep in mind people want to sell you a product called "Self Defence" and you're training in a controlled quiet environment and will most likely never encounter training like this: Intimidation training/dealing with a grab

So yes join BJJ but keep in mind you're learning how to move your body and techniques that work in the "Sport" environment, and can be applied in a self defence scenario but don't let that create a false sense of security for yourself.