She's 14 and has had an aversion to all sorts of fruit. If I am slicing peaches she would move her bowl away, or if any strawberry juice or I used the same knife to cut an apple she will go hysterical. Blueberries peeled or not would be poison to her. Any berry. She does have allergies and anaphylaxis to peanut and nut. Just be careful, sometimes kids have these aversions because they can be allergic and are detecting a slight tingle in the mouth which is a sign of allergy.
A lot of nutrients particularly vitamin C are just below the skin, so peeling you lose them. If I make chips I never peel potatoes, that is the most nutritious part. Just scrub, carrots, potatoes. I wouldn't peel then they expect them peeled all the time, friend of mine still peels her kids apples and they are 11 and 14! I would present it and positive praise if he tries it, but not too much pressure, plus watching other kids eat them and praising the other kids for doing so. Or dipping in yogurt or even chocolate, or maple syrup. Chocolate fountains with fruit is the best thing for a kids party - but outside so much mess! (use so much chocolate though, so maybe a chocolate fondue instead!) Grape crunching competitions are good. Or throw them up in the air and catch them in your mouth and crunch! And berry smoothies, can make with yogurt, add a bit of ice-cream on top, or even cacao that is another antioxidant and you add a bit of syrup to sweeten. I'm into agave nectar as a syrup, it isn't so sickly sweet, but honey is good, or maple syrup, mix with cacao and berries.