My enamel looks like some of its wearing off how do i strengthen it. also can i still whiten my teeth.

Strengthening enamel: Stay away from acidic foods to not make it worse. Use tooothpaste with flouride and acp (amorphous calcium phosphate) which helps rebuild enamel a bit. Its available at your dentist usually. You may whiten if the damage is not too bad, but use a professional system from your dentist with acp as well. Have your dentist do an exam, check for acid reflux at your physician too.

Topical fluoride : Go to your dentist and have Fluoride varnishes when you get your teeth cleaned. Enamel does sometimes wear down with biting forces and/or over brushing. It also gets darker with your age. You can bleach your teeth at any age.