I think 18" is fine, but put the plant directly under the light, not aside. If the light is too far, the plant stretches, if close, it gets more bushy and less stretched.
Regarding nutes, I would wait and see. For me, I noticed they start to stretch after weeks 3-4. The dark green color of your leaves indicate it is not lacking any nitrogen. I would just wait and see how it behaves before adding any nutes with more N and wait to see if the green goes lighter, if already flowering, I won't add any more N.
I was going to ask you about ventilation:
You stated:
"right now im sitting at 74-81 with an oscilating fan poking out the bottom of the tent, and one pointing at the light."
https://www.rollitup.org/attachments/image-jpg.3356398/
You need to extract hot air on the top and inject fresh air from the bottom. Hot air goes up naturally. You are currently making a bag of turbulent hot air in the top of the tent if you are not extracting any air up there. You are also spending more watts unnecessarily by using those 2 big fans in that way. Are the lower vents open?
I just posted a new thread for sharing my setup with you. I'm not using any expensive ventilation but I think it is working just fine on a very low budget. ( $30 for 2 vents ). I take fresh air from the bottom intakes, I move the air below and AROUND the leaves and then I extract any hot air and humidity at the top vents.
https://www.rollitup.org/t/20-x36-x60-tent-150w-led.862951/