I wouldn't say I'm oblivious to this, there are occasions where I am 'envious' of what a younger person has achieved, especially if I worked with them when they had a more junior role (i.e. I'm thinking "how has that person managed to land that job in that space of time without more stepping stones in between?"). But in some ways that can be inspiring, making me think that I could achieve similar.
My current employer is the first place I've worked where I think I'm significantly older than the average person. The next 'rung up' is mostly populated by people seemingly about 10 years younger than me and the founding directors are about 5 years younger. This isn't something that bothers me, I'm happy to work with younger people in a position of seniority. There have been rare occasions when I've felt their lack of experience has perhaps seen them backed into a corner and made slightly difference decisions than I would have done but that doesn't mean to say they don't have the aptitude to succeed (I'm sure I made similar errors at the same age).
I think this discussion also needs to be considered from the other side, i.e. if you are a young person in a position of seniority, how does it feel to engage with older subordinates? I never really had a problem with it but I was mid-30s before I moved into management anyway. Occasionally I see young people in senior roles be a little hesitant when dealing with older, outspoken individuals.