If your baby really doesn't like being on her tummy, leave it for now and try again another time. Bear in mind that babies develop differently, some more quickly than others. If your baby isn't rolling over by the time she is six months or seven months old, talk to your GP or health visitor.
Some men stop growing at 18, some at 21. Some men grow really quickly early on, and slowly grow taller until they have hit somewhere between 18 and 21, while others grow quickly later on and some just grow gradually. So, only time can tell you, no one else can because everyone is different.
Men grow the most from 12 to 16 with the increase in height being as high as 12 inches in normal cases. Boys actually gain the most weight during this period, too. The growth during this time period is mostly in the extremities with the legs, feet, arms and hands growing the fastest.