I feel your pain. I've got 15 tomato plants which are as much as two feet high and are desperate to go outside. (Some are for friends.) And perhaps 50 climbing french beans and forty-odd sweetcorn plants, and untold multitudes of courgettes and other goodies. And I'm about to take the same leap of faith, because we're running out of window space in the house.
Ordinarily I reckon to get my greenhouse and outdoor tomatoes out by early May, which is about three weeks earlier than the textbooks say (we're in Wiltshire), and I've never had any frost problems with them. This year has been colder than usual, which means it hasn't been possible to even think about doing that. But I'm looking at the forward weather forecasts now and I can't see any night frosts between now and the end of the month. (Depending on your location, you might have something different.)
Greenhouse should be safe now, anyway. If you've got any fleece, keep it handy. Good luck!
BJ