That's very hard to answer because the growth rate is not a straight line. Some periods children grow a lot in a short time. Here's some things a peditrician once told me: children show signs when they are about to grow like chubby faces, increased appetite, excessive tiredness, complaints about pains in legs or arms and needing new shoes. When you see these signs, it means their bodies are getting ready to grow a bit. As children get older many of these signs tend to disappear. Sometimes they start again in early adolesence. It's very possible your DD will make it. My suggestion would be if she is very close, find a pair of sneakers with a good thick heel. It works for us. We only do this if our DS is close. Although he would love to do the extreme rides, height restrictions are there for a purpose. If he's close we try any trick we can. Good luck! My son finally made the 44 inch mark about 4 months ago. He's five and will be 5 1/2 by December. That puts him at the 50% for boys his age.