Asking someone of the opposite sex and is just a friend to come with me to a...
Well of course it is ok to ask, that is after all what nudist friends are for. I'm sure if she is showing interest in the nudist lifstyle, then she would be happy to join you on a visit to the beach.
Instead of straight asking her you could just once raise a topic of nude recreation/nude sunbathing with her and see her reaction. If she knows about your nudity already, then you possibly know how naturally she takes it. So according to her reaction, either invite her or not. Also an option if she is not willing (yet) to be nude is to find just a nice natural spot or a clothing optional beach so you could be nude and she could have smth on.
nude beach. Is that ok?I know someone who is a pretty close friend of mine who told me that she went to a nude beach before and I am thinking of asking her if she would like to go with me. Since we're just friends, is it ok if I ask her this?
If she went to a nude beach before, why not find out, if she had a comfortable experience, did she like it, or not?