Oh Baby Mini! They are super cute. That said, I would be extra careful on foal watch. Mini's due to their small size are prone to trouble delivering live foals. The chances of you saving the baby are slim if the mare has trouble (you only have about 45 minutes from the start of labor). Still, getting fast help can save the mare.
Also, the standard issue baby mini is on average 10 times fuzzier then any other foal. Its like the miniature horse womb is subject to sub-artic temperatures with the amount of hair the come out with.
I hope you have made plans to geld the father or separate them unless you plan to get into the mini business. Mares go back into heat 7 days after foaling, which means you can have a pregnant mare 7 days after foaling.