my bitch is 1 year old and hasn't had a season yet, does their personality change i have noticed that latley she is spending a lot of time just moping about and when my old girl wants to play she is really aggressive towards her , it is the first time i have had a unspayed bitch ,,what should i look out for thank you

Sounds as if she may be coming into season - lots of bitches seem to suffer from "PMT" ! keep a close eye on her when she is in season as some turn into proper little floosies when they are ready for mating &, however good she normally is, she may turn into an escape artist overnight!! Once she's had her season, she should return to her normal self - perhaps a little more "mature" in her attitude.