Can I start to flower my plant???

Hi fellow growers. I'm having an experiment with a single plant. I don't want it growing too big so I topped it yesterday. I am going to leave it a week to recover. Then can I start to flower it ? I don't want it too big so it's only going to be a small plant I hope. But I want big buds so will I get a good ish yield when flowering this early? I'll post a picture. Thanks guys