Personally, I don’t think you should attempt to stop flirting with anyone – unless they’re either married and wearing a wedding ring or if they are currently standing in front of you with their boyfriend.
Flirting is a harmless activity that generally puts people in a better mood. The secret is knowing how to dial it up or down, depending on whom you’re flirting with.
If you flirt with a woman who looks lonely and she’s twice your age, you may make her entire day. If you flirt with a girl your own age who’s single, what’s the problem? That’s what you’re expected to do.
Another benefit to flirting is that it helps hone your social skills and builds confidence.
I don’t see a problem with your flirting with girls, and I see no reason to stop doing it. Just start off easy rather than dialing it up to “10” right off the bat.