I am getting a gas stove delivered to replace my existing one. I am in a condominium unit, but I don't see a gas shutoff valve, there are ones for the water inside of my unit. I thought it may be this brass nut piece sticking up in the middle, so I put some wd-40, but it doesn't seem to turn. Should I try to turn it more or is there no shutoff valve here? Thank you!
Yes, that appears to be a valve. Note that it can only turn 90 degrees (clockwise as it sits), constrained by the lugs on the side. The line indicates gas flow (in line with the pipe as pictured open, crossways to the pipe closed.)
If it requires excessive force to operate, better to have gas shut off upstream and replace it, rather than risk breaking it.
WD-40 is not really the appropriate thing to use on stuck items - it has a particular use (displacing water) and it's a poor excuse for either a penetrant or lubricant.