Is it normal that... I was not invited to my son's playdate?

This mum found herself in a very awkward position on her son’s last playdate. Can you help?

My son is four. Most of his friends he’s had since Mother’s Group and I know them all.

Lately he’s been invited to play with new friends from preschool, which has been lovely for him. I enjoy seeing his confidence grow as he  comes out of his comfort zone.

But, is this a bit weird?

A mum from preschool asked me at pick-up if I'd like my little boy to go to her house to play with her boy. They're friends at preschool and get along really well. We made a date and a time.

But when I got to her house, I was a bit shocked to realise that she wasn't expecting me to stay. At the front door she ushered my son in and her little boy was really excited to see him, but then she turned back to me and asked what time I'd be picking him up.

I was really flustered, because I've never left him anywhere (other than with my mum) for any length of time before. I mumbled and muttered and said something about him expecting me to stay, so she let me in and we spent a rather awkward hour watching them play and making small talk, but I got the distinct impression she had other things to do and didn't want me there.

Now, she's a really nice lady and I don't get a vibe that she wanted to do anything sinister with my boy (!), but is it normal to drop a four-year-old off for a play at a strange house? Am I weird for not being comfortable away from my son, or leaving him like this?

What do you think?