I want to be ineligible for surgery

I'm 19 and basically my parents are forcing me to get the surgery and I really don't want to, But I agreed to get my eyes checked to get them off my back but now I'm worried I'll be eligible and I'd have to do the surgery right away

So my question is, What makes someone eligible, I heard you need to at least be 20 to get it so hopefully they'll just say I'm too young for now but maybe they won't... if I tell them I get dry eyes often can that make me ineligible?