My boys were 14 and 17 months before they took off. The second one wasn't in a hurry at all and I remember getting sick of having to carry him around outside as there are bullants etc here. If anything, crawling for ages is really, really good for their development - lots of cross brain patterning and coordination skills going on which helps for things such as reading on a page, left to right, cycling on a bike and alternating the legs, balance.... I'd be more concerned if your child skipped the crawling stage and went straight to walking, like my nephew did. Your DD will walk when she's good and ready, it's just frustrating when friends have kids the same age and you get comparisons happening. Just know that she's doing a lot of brainwork when she's crawling, clever little thing