As a teen girl I understand whats its like to not be confident in how God made you. I'm praying for you and how this is a blessing to you!
Have you ever looked in the mirror nitpicked every imperfection you see in your reflection. Every teen girl has a list of things she wishes she could change. To combat these thoughts Psalm 139 comes to mind. Specifically verse 13 and 14, but I want to draw attention to verse 17, "How precious to me are your thoughts, Oh God! How vast the some of them!"
When we say things such as "I'm ugly" or "I hate....fill in blank". We don't stop to think how this makes God feel. Like verse 17 says, Gods thoughts should be precious to us because of how great he is. God is so powerful and mighty. Think about when someone comments on your hair or clothes it makes you feel special well think about the creator of universe saying your beautiful it means all the more.
The better we understand Gods perfection the more we understand the meaning when he calls us "fearfully and wonderfully made". Now knowing this together we can encourage each other and ourselves to remember who calls us "fearfully and wonderfully made."