Yes by around four weeks at least-if they are half-hardies they need heat to germinate and good light and frost free conditions to grow on.
Now is not the time- there is no advantage at all in starting too early
I sow mine in March because they need warmth and light to germinate and grow and can grow leggy if you get them to germinate early and then the weather is cold and gloomy. Depends if you want to spend on heating the greenhouse as well. But I know others in this forum sow earlier.