IMHO, shallow is being concerned
exclusively or primarily with superficial characteristics.
Who the hell doesn't want to date someone attractive? "No thanks, I want to date someone I find repulsive."
It's a different story if you'll only date lawyers, or people who drive a nice car, or have a certain profession or salary.
THAT'S shallow. You're attracted to who you're attracted to. Now, if your standards are unrealistic or immature ("her hands are too big," "he has funny-looking nostrils," or whatever), or if looks are the ONLY thing you care about in a potential partner, that's a bit shallow.
And liking the way you look isn't shallow. However, excessive preening and carrying on about your appearance is vain. It's one thing to be confident; quite another to be self-absorbed.