Age must not be a barrier if you really are want to learn things, because in our dojo, we had two practitioners that is more than 50 years of age, yet they are so active and energetic.
Being a girl and doing Martial Arts doesn't mean she is a weird, it just show that she is arts lover and willing to achieve new kind of ability.
I am a girl and I do martial arts, and age has nothing to do with it, the only problem is if you go to a club where there is like 6 year olds going it can make you a bit self conscious :S hope i helped
Absolutely not! You are NEVER to old to learn a Martial Art, and its not weird at all for a girl to learn Karate at all. I say to go for it, and if it helps, maybe try MMA instead of just Karate
Ha ha, In my dojo we have people who are 30-40+ wanting to join, and they do fine.
Go for it.
And no, it's not weird for a girl to learn a martial art, In fact there are some girls who train the same style as me, who could whip my ass...when they are holding back. Gender and age don't really make much of a difference, so give it a go!