I'm tall too (5'11"). And I have to say there are different ways of being told you're tall. Sometimes it genuinely is a compliment and comes out as such. Sometimes it's just because it occurs to them and they just say it because they notice it. Douglas Adams has some very funny things to say about human beings' propensity to point out the very very obvious. I mean what do you say in return?
"You're very tall"
"Am I? God! What happened? I was 5'2" yesterday!"
But sometimes it's said in quite an aggressive way, and can be very upsetting. And generally by people who are intimidated by you. I think back at all the people who've upset me most by making comments on my height and they were - well, a bit inadequate in themselves in the main, for various reasons. Once, three years ago, a very insecure girl a fair bit older than me reacted to me being complimented by someone else that I didn't look like I was 30 (my age at the time) by suddenly saying:
"Yeah but you're TALL though aren't you? I just look at you and all I see is TALL. I once dated a married man who was married to a woman your height and you can see why can't you? I mean, it was a challenge to his masculinity isn't it? You can see why he needed to be dating someone else!"
I replied - more bemused than anything else "Erm - that's a little bit offensive"
To which she announced she wasn't going to be spoken to like that and stormed off.
If your daughter really is a bit of a stunner (and I'm sure she is , perhaps she is a bit of a magnet for the latter category. Wouldn't surprise me.