Beauty Mini Mare Due???????

In November our grandchildren had two minis follow them home!! A black registered mare and a bay unregistered stallion. The two are very cute but I fear we maybe adding a wee little one sooner then later. The grandchildren are thrilled that there maybe a bundle coming but not knowing a due date is a bit scary for grandma!
The pervious owner said "due this summer if bred " but the pair has been together since last Jan., when the pervious owner bought them. I think summer maybe wishful thinking. Both are decked out in winter woolies so it is difficult to really gage how big Beauty's belly really is. We will just keep watching and monitoring her looking for any changes in her udder and shape.