Normal lang ba laki ng tyan ko for 5 months?

I’m 17 yrs old and obviously my first time. Pinsan ko po kase nakita ko sakanyan bum pic nya nung 5 mos sya and pinagkumpara ko sya saken ngayon naliliitan po ako. Medyo nag worry po ako, is it normal or is there something wrong? The first pic is mine and the second one is my cousin’s