As you can see, some are more pronounced than others. While some have a softer, rounder form. Little Children's noses are a lot different from adult's noses, as you might have already noticed. Fun fact about noses (while we're on the topic), they continue to grow all throughout your life. Albeit very slow.
So, have fun with this and see if you can notices any differences among the noses of friends and family members. If you have friends with different ethnic background, you will probably notices the differences their too.
Just remember to have fun with your art and not to make it seem like work!