Hello and welcome! Your beardie will be fine with you working a full-time job. I know from experience; I work full-time and sometimes 50+ hours a week, and when I come home my dragon (Bones) is usually basking and ignores me until he decides he wants to cuddle haha. If you get a juvi, since you will be working, I just recommend holding him and interacting with him during the times you are home. Bones was really temperamental at first as a juvi, but the more I started holding him, the more relaxed and tame he became.
As far as lighting goes, I have three bulbs for my little guy: an infared one for night, a basking daylight bulb, and a full spectrum bulb. I originally had just the full spectrum bulb and an infared bulb, but even though the tank was reaching an adequate daytime temp, Bones was soooo lethargic and showed disinterest in eating. I noticed he wasn't basking at all, so I bought the daylight bulb for while I'm away at work. So far this has worked for me and my juvi, and he seems extremely happy and started eating and being playful again after I bought him the daylight bulb:
Getting ready for work: Full spectrum bulb
At work: Daylight basking bulb
After work: Full spectrum bulb
Nighttime: Infared bulb
Other more experienced members might have more helpful suggestions, but this is just what I've noticed so far =) Heads up, buying all the startup equipment to maintain a dragon is expensive. I would recommend waiting a month or two into your new job so you can save up a little bit before purchasing a dragon. Also make sure you disinfect the tank you bought at a garage sale before you let your dragon live in it -- you never know where that tank has been before you bought it!