Can you segregate patrons with children at a restaurant?

I went to eat at a local chain restaurant for lunch today with my one-year-old daughter. I asked for a booth and a booster seat and the host said there were no booths available but she could get a table with a high chair so I said ok. On the way to my table I saw a couple of open booths but since I have worked at numerous restaurants I know there could be many different reasons why she didn't seat me there (server had just been double sat etc.) then I was sat in the very back of the restaurant behind a sort of glass, window barrier area that was packed full and very loud. As time went on, I noticed every single table back there had kids, and when I looked in the other areas of the restaurant there was not a single kid. After lunch, I called my sister and she said the same thing happens every time she goes there and that's why she doesn't eat there anymore. Is that legal? Seems like age discrimination to me. Also the middle area had much nicer tables and chairs.