It is so sad that you're being harassed. You seem like such a kind, curious, and fun young woman (strictly from your posts on TERB). To be honest, I would consider moving if I were you. After 3 robbery attempts, they're going to be successful eventually and who knows where it escalates from there. Robbery goes far beyond harassment IMO.
Where is this stuff happening?
Sure, standing up works in theory or did in the old days. Occasionally I've seen some of the Somali/Ethiopian teens that go on like they're bad even though they're 6 feet tall and 90 pounds wet. To an average man, these teens are no physical threat, but if they're carrying an illegal gun, the whole power dynamic changes.