holding head up??

brandyo83

I have a three month old daughter that is very chunky. She is having some difficulty holding her head up completely on her own. when I set her up in the seated position she holds her head on her own but when I pull her up from a laying down position she does not hold her head until she is sitting up. Should she be holding her head up all by herself already? and should I be very concerned. My older daughter held her head up from like two weeks old so i am very concerned about her development. Please help or offer advice. Thanks