pup going in heat

Question
Ok I got this female Maltese about 2 months ago, meaning she is 4.5 months now. But my question is can she or will she go in heat soon? Because my male Maltese is acting strange like sniffing her and rolling her over. So are these signs that she is going in heat or fixing to go in heat?

Answer
Tiny toys go into heat at 4/5 months thou some wait until 6 or more months and the cycles are genrally had every 4/6 months keep them seperated if you figure shes coming into heat she will most certinly die or pregnancy problems if she is bred so young and small.