my bitch was mated 3weeks past tuesday, im really looking for signs here but yesterday i noticed something dangling from her vulva. i got tissue and wiped and it was clear mucus about 2cm long. no more since, it did not have an odor.... is this a pregnancy sign? shes never had this before

Yes this may well be a sign of the bitch being pregnant.

At 3 weeks there is often another clue.  I have always checked my bitches nipples on day 21, and they have always taken on a brighter hue.  So if you have rosy nipples as well as the mucous I would take that as a confirmation.

Sorry, I don't mean if you have rosy nipples.  Not you personally. 

Coffee all over the screen now Jean :-D :-D :-D

This is good, just make sure it doesn't turn brown/ green with a strong smell.

haha yes her nipples have changed more pinkish/ rosie too