I couldn't wait either! I put 6 flats of flowers outside with more to do next week. Right now there is lots of snow cover so that's good. I'm hoping it's not to early. I have never started tomatoes for wintersowing. Might try that later but I won't sow them until March. Marg

Have you ever had tomatoes sprout in the spring from fruit that dropped the year before? I have..that's nature 'wintersowing'. It can happen, and you probably will get germination. Wintersowing in March just means more will probably germinate (less chance of rot).
If the flowers were perennials, or hardy annuals (ones that reseed naturally) then you should be ok. Annuals like impatiens, yvonne's salvia, that don't readily reseed shouldn't be sown until April (in Ontario) for best results.
Let me know if you need some more seeds...;0)