"Too late" vs. "just right" or "too early" depends on when you expect to put them in the ground, whether "ground" is outdoors in the garden / plot, or pots in a greenhouse.
My predicted last frost date is April 15, so I want big strapping plants by then. Last year, we actually had frost later than that, but I want my plants to be ready. I started my tomatoes in late January this year. Initially, they were indoors, started under lights. Mine are in three flats, not too difficult for me to move, so on days when it is warm enough (my rule is 10 C or warmer), the flats all go outdoors on a bench to get the sunlight, then move back indoors before the chill at night. Here it is mid-February, we have already had stretches of a few days where the flats haven't needed to come back indoors. Tonight they will, it will freeze hard tonight. I admit this is a lot of fussing around, and probably not for everyone, but I already have sturdy but compact / small tomato plants. By late March they will probably be in pint or quart-sized containers, mostly outdoors, but occasionally brought in (open garage) to shelter through a cold night under a tarp. By that last frost date, they will be in half-gallon containers or larger, ready to plant outdoors when the conditions permit. You can "extend the boundaries" a bit by selecting tomatoes bred for colder climates (Stupice, Anna Russian, Azoychka, or Beaverlodge Slicer are just a few examples).
If you try this, just modify to meet your own conditions and preferences.
