How do you know if your friend is pregnant?
Is your friend your age?
Is she having sex? If you two are really close then you should be able to just ask her.
If she is, maybe she's not the kind of person you should be hanging around./ I mean 13 and pregnant?
well if she is wanting to know then use those tests you buy fomr clinic's and stuff but if you are trying to find out... then see if some of the siptoms are there like sore breasts or moody or w/e..anyways good luck
moddyness and morning sickness or somthing like that lol and is they change there personality lol good luck!
You'd probably have to ask them.