Forcing flowering does not cause reduced potency, and will not kill the plant. When you flip a plant from Veg to 12/12 it's being forced to flower.
It's actually very common to go straight from sprout/seedling into 12/12 with absolutely no bad issues. Google "12/12 from seed". People with very small grow spaces do this all the time with great results.

During Veg it's best to use 5000K or 6500K bulbs (blue). During flowering it's best to use the 2600K or 2700K bulbs (red). If you're using multiple bulbs it's good to add at least one bulb from the opposite end of the spectrum - for example in Veg maybe do 4- 6500K's and 1-2700K, and in flowering maybe 4-2700K's and 1-6500K. I'm just using those amounts as an example to point out that mixing both types is a good thing. You can use any number you'd like.
I hope this helps.

BTW, your plant looks pretty good! :thumbsup:
Gnatty Reviewed by Gnatty on . new green new grow please help im a new grower i have only 1 plant on the go i have them under 3 100 watt and 2 40 watt cfls and a pc fan blowing on it it's only a small space so i have low stress it it looks fine i add nunts once a week and normal water inbetween i veg it for a while and im flowering now 12 on 12 off for about 4 weeks but im not getting any signs if male or female can any one help me or give me some advise thanks very much big the grow.... Rating: 5