This appears to be a sedum. The leaves suggest sedum nussbaumerianum, but the flower is more like sedum ternatum.
Sedums are perennials, but they do die down to the ground in the winter and put up new growth in the spring, if they are hardy in Maryland. If they are not hardy in Maryland, they would die outside. This means they are more tropical, then they would have to be brought in for the winter and treated as a houseplant. Since we don't know for sure what species you have, we recommend that you continue bringing it in for the winter.
(Annuals must be grown from seed each year. They only live one year.)