I have owned 5 Dogs (all Male) at different times. Recentley we decided we would have 2. So along with my 5 year old Doberman dog we now also have a 20 week old Doberman Bitch.
I have no intention of breeding her she will be spayed at the earliest opportunity (Vet says 7/8 months). My dog has already
been done.
I have never owned a bitch before but is the below normal.
She has lateley been depositing very small amounts of urine (Not Blood) around the house and has tried to mount my dog. My dog is paying particular interest to her rear and has tried to mount her.
I expected this at 6 months + but is this normal at  20 weeks ?????

Unlikely but possible, I would have the urine checked for infection, just to be sure that is not the problem

I would go with what Jackie said - it's probably best to get her checked over.

I have seen a bitch come into season and get pregnant at 16 weeks old :o However, that was a JRT and smaller dogs mature faster.

Edited to add: That was meant to be a shocked face *lol* - not a yawn!