How to defend myself against a bigger and stronger aggressor?

i'm a very short woman (about 4.8 ft) 46 years old. if I were to be attacked for example from a 20 year guy 6.2 tall and of course much stronger than me have I any possibility to beat him or at least to hurt him enough to run away ? how can I do ? however i'm getting a self defense class in a few months but i just want to know if it's real that I can resist to a bigger aggressor