If I am briefly texting back and forth with a man and he suddenly replies isn't it past your bedtime does the tone of that question seem rude or not and how should I respond?

.. if that was me, i would take it as a joke... because I know the guys I text would say it to be cheeky. If you are worried he is bored texting you.. surely he'd just stop replying not text you saying the above. If this is purely a text/internet relationship, he may be testing you to find out your true age. It is possible he is being playful or flirting. It is unlikely he is being rude.