I think this is far too early for corn,this is one veggie that planting early won't help give you earlier corn, in fact it can have the opposite effect, three weeks at the very most in a pot and it needs to be in the ground otherwise its internal clock is disrupted. You can plant the older varieties and pot for longer but so few people grow them now.
I don't plant mine till May, early or mid depending on the weather unless weather is really good and I take a chance on an early planting.
I would move the corn from the house to the greenhouse, it will slow it down a bit which is a good thing right now,
I will plant some corn this week ready to go out if the weather is OK in May but I will plant a second batch in Mid May as a back up if it turns cold suddenly and it can't go out. It sounds like a waste but usually if I do this I grow both, only rarely do I plant two though.The weather seems good enough to have a go this year so I will.
XX Jeannine