No Sleeping

Hello I have a one year old little girl and she still wakes up in the middle of the night to play. It is usually around 3am and she will cry until 4-4:30. I will go into her room 10-15 minutes into the crying episode to make sure her diaper is clean. If I have to change her I will and then I immediately put her back into her crib. Sometime she will only cry for 10 or so minutes after I leave and other times she will cry for longer. I know she knows I will come in. Should I just not go into her room at all??? During the day she usually she naps twice. One in the morning and one in the afternoon. I am trying to see if keeping her up longer helps but so far it does not. She is not cranky at all. In fact, she is quite a happy baby (most of the time). If she has a later nap (around 3-4pm for 30 minutes) I try to keep her up a little later. But that doesn't seem to be working either. Her normal bedtime routine is first to have some cereal about 15-30 minutes before bed, a bath, bottle (although she doesn't usually want it) and bed.