Lemonberry Haze Auto

She is growing so fast now and im 3 days away from end of week 4. I have some slight discolouring on the tips of my highest leaves which I think is light burn, since i forgot to check the height, so I have raised my light again so its now 21 inches from the top of my plant. Apart from the discoloration on the tips she looks stunning I can see the difference from morning pictures and night time ones and I am staggered how well she is going. Im thinking she is looking like she is showing signs of pre flowering so going to switch the light to flower on the 1st Nov. That brings me up to date to where I am currently. So far not really any issues however she is looking like she is needing some of the lower leaves trimmed to let more light in but I am again a little bit scared so ill just pin them out the way at the moment. Thanks for looking.