I often send text messages to my girlfriend. Will she be angry?

Generally speaking, not. Of course, it depends on your relationship. If the relationship is not very deep, she may get bored, think you are bored and ask everything (of course, this only refers to some people). If you get along for a long time and have a good relationship, then she will only feel a little sweet and think that you care about her. Anyway, although some people will feel a little annoyed, when it comes to being angry, there is generally no such thing.