Is this considered as pale green due to insufficient nitrogen?

No, signs of nitrogen would start at bottom as it's mobile. Light green with no obvious starting point is always a micronutrient/s. Micronutrients start to have problems when ph gets a little high with exception of molybendium. First question to ask is do you PH your feed solution to the proper 6–6.5 range for soil? if not begin doing so immediately as the plants require a certain ph range to uptake nutrients. Possibly drifting a little high.

I have same problem atm early flowering and have been adding 0.5ml p litre of nitrogen nutes and 1ml p litre of some cal mag. i think its improving slowly but it is hard to tell under lights sometimes. Maybe do next watering the same and add some cal mag and small amount of nitrogen see if she improves any. I think she is on the early side of any nutrient deficiency so could be easy to fix quick before it gets any worse.

Hey there 1st off your doing a great job Well yes when your plant is flowering it need some nitrogen when it's going thru the strech it needs a decent amount but even durring flowering and late flower the plant will want some nitrogen. I suggest giving it some type of cal mag alot of cal mag has a 5-0-1 or something similar Be cautious at 1st don't make the plant get messed up by to much thinking it needs extra fox farm cultivation nation has a good cal mag that will work great for you. Your plant probably needs some cal and mag aswell so that will hit all 3 possible problems Just to be cautious when you water I would catch some of your run off water and get a ph level. If the ph is off then flush 4 or 5 gallons if water thru the pot with water ph to the correct range of around 6 to 6.5. Also I'd consider top dressing your soil with some worm castings and some mycinohaze should help the plant get the nutrients better

Without day light or night time and flash - you dont see real colour. Could bet she is closer to healthy green , than any pale ... I personally would not trust any recommendations made just from this photo ... Leaves clawing down, either you watered her very recently, or you have some sort of problem/deficiency. Thats obvious, but rest is hard to know.