How much is to much light ?
It doesn't really work the way you are thinking. As long as you can control the temps and supply the food needed to grow, the more light the better. But you are upping the plants metabolic rate with more light....you need to support it with food/water/temps/rh/co2. As long as you do that, it's hard to have too much light. I've done 4500 in a 5x10 w/co2.
So it's not a question of "too much light." It's a question of striking the right balance. The balance of what your setup will support for optimal quality and yield. And the first thing I thought when I saw your pics was that you need more light. I would do at least 400 veg and 600 for flower in a 4x4.
See how small your plants are? You've gone through all this effort and time, to yield very little. You will see once it's dried and cured. If you had more light, you would yield substantially more. One plant would out yield 4 of what you have there. But too much light and not enough cooling = heat problems. Too much light but not enough nutes will cook your plants. Too much nutes but not enough light will burn the plants. It's all about the balance. Right now, you are way to lean on light.
It looks great for your first time. If your worst mistake was not having enough wattage, that's an easy fix.
