Im going climbing with one of my guy friends and im 5'3 about 135and he is almost 6ft and probaly has a good 60 pounds on me.

Im going to Rock'n and Jam'n. We do not have a 3rd person to anchor me down, do indoor places have devices attacted to the ground to anchor?
Im new to climbing and l think those exist, l think l remeber seeing themthere when l went with my rock climbing class in school last year.
Im an 18 year old girl btw. he is the same age.
Im an 18 year old girl btw. he is the same age.

Most do have anchor points on the ground. If not see if an employee of the gym could either back you up belaying or offer a solution.

For the top rope routes, they have to have a way to anchor the belayer to the floor because a falling climber could pull you all the way to the ceiling - ask the gym staff how to anchor.

For lead routes, they often do not have anchors because the climber can only pull you up to the first bolt and usually the belayer wants to lift off the ground to soften the impact for the falling climber.

Good Luck

It does not matter that he is bigger, u can still catch him on lead (you will just go flying up to the first bolt, so be ready). Botls r always close together in a gym anyways, so there wo not be any big falls. You would not want to be anchored down when he is leading because u would not absorb much of the fall with ur mass. Especially with those silly GriGri devices they make u use, because those things do not allow any rope through during a fall, they just lock right up.

For TR, they likely have ground anchors, so u wo not have anything attached to u while belaying.