Is my dog in heat

Question
Hi, My name is Megan and I have a Sheltie about 17 months and I was wondering if she is in heat because our other dog has "humping" her and she is always trying to get between his legs and she puts her butt in his face? So is she in Heat?

Answer
If she is in heat her vulva will be very swollen and she would have been bleeding for the last week or so. You can see that is it is swollen by looking at it.
At 17 months she should have already been in heat once.

Unless you are planning to breed her to a purebred you need to get her spayed as soon as possible.
There are plenty of unwanted dogs in the world now! Don't add to them please!!