Prime has been suppressed after the Second Vatican Council. As long as you pray them during the day they are for you are doing ok, especially if you aren't promised to pray them. Generally, I try to follow the following schedule:

Morning Prayer (Lauds): 6-9am or whenever I get up in the morning.

Daytime Prayer (Terce, Sext, None): Whichever one works best for me that day with Midmorning (9-11), Midday (11-1) and Midafternoon (1-3) respectively.

Evening Prayer (Vespers): 4-6

Night Pryer (Compline): anytime after 7 usually shortly before bed.

Office of Readings (Vigils): Anytime I have a good bit of available time, usually immediately before morning or evening prayer.

Ultimately, ones intention is the most important thing. You should pray the office so that it is feasible for you and that it encompasses your entire day (with morning and evening prayer being the most important hinges). So if you can't pray evening prayer until after your 12 hour shift at 7pm then by all means pray Vespers then. Just make sure to pray often and pray well.