One of the reasons DD1 got vaccinated was because her 18yo college friends had a heart transplant recently, and for her the Covid vaccine probably won't work. It's not just the older population you're protecting by getting vaccinated.
Dd has some vulnerable friends, CEV and CV, and it was one of the main reasons she wanted her vaccination ASAP. She also saw how ill I was with covid, I'm CV and this was just a moderate case of covid, and didn't want to take that risk with her friends or any of her vulnerable family.
And she also wanted to reduce the risk to herself too. In the same way she asks me to pay for her to have a flu vaccine each year, she wanted the covid jab. She's had one bad case of flu which made her really poorly over mock exams and didn't want to risk that for other exams hence the flu jab. And she felt the same re covid. She'd rather reduce her own risk.
Plus she really wants life to get back to normal more quickly and knows that one of our best chances of doing that is to get as many people vaccinated as possible. She wants to travel, go to festivals, go to clubs etc - so yes, partly it's a selfish reason as she knows she has a greater chance of doing those things if fully jabbed and if more and more,people are fully jabbed.
Every single one of her friends, at home and at university, have had at least one vaccine and due to have second soon. She doesn't know any who hasn't. Even the needle phobic friend has had her first - it took her a while, she got support from her friends and boyfriend to get her there, they spoke to the vaccine centre on arrival, they got her a laid down cubicle as she has been known to faint with needles, and she got it done and out of the way. So in my experience most young people are keen to be vaccinated against covid for a wide range of reasons.