At 13, you don't have as many freedoms or responsibilities as older teenagers and young adults, so getting a girlfriend at this age can be a challenge. After all, you can't drive by her house and pick her up to go out to a movie. You're not old enough to drive and you're not old enough to work in most states, so you don't have extra spending money to pay for movie tickets. However, getting a girlfriend isn't impossible if you know how to show that you care and are willing to spend quality time with a girl.
Talk to a girl you like. Don't ask her to be your girlfriend yet, but find out about some things she likes to do or activities she's interested in. Find out things you have in common with her and talk about those together. If you need to, do some research about things she likes that you're unfamiliar with. This will show her that you're a friendly person that has a genuine interest in her.
Be in a good mood when you're around the girl you like and try to get along with other people. Even though you might think it's manly to fight, most girls don't like boys that are confrontational. Instead, be nice to everyone and do your best to smile a lot. This will show her that you care about people, that you can be trusted and that you won't lose your cool in difficult situations.
Invite her to hang out with you and your friends at a social gathering or in a public place if your conversations are going well and you think she likes you. This gives you a chance to get to know her outside of school. You can invite her to go watch a movie, eat some ice cream, hang out at a local park or play laser tag. Let her know that others will be around too so she won't be so nervous about accepting your offer. While you're hanging out, pay special attention to her and treat her in a special way, letting her know she's more important to you than the rest of the group.
Ask her to hang out with you on a more private date, if things went well when you went out with your friends. Ask your parents first, because there's nothing more embarrassing than getting a date and backing out on it because of your parents' rules. If your parents or older siblings aren't willing to drive you anywhere, ask if she can come hang out with you at your house. Do something together that both of you enjoy. If things go well on this date and you're confident she likes you, you can ask her to be your girlfriend. If you're still a little unsure of her feelings, go on one or two more dates with her until you feel confident in asking.