Don’t know how I missed this, sorry dude. Hopefully it’s not too late, but I think what you’re feeling regarding the new civ job is normal - you’re excited at the “newness” and actually having a “real” job for the first time in your life. If you were a normal college student, it also probably feels like a shitload of money and perks. I’ve worked with tons of engineers and been around “that world” for years (from a pilot perspective) and guess what - lots of guys working late hours, “non-standard” times, Saturdays, etc. Especially newer guys - the grass is not always greener, just different.
I think you are likely to significantly regret passing up an interview in a year or two after the “exciting newness” wears off and your engineering job is just a paycheck to you. But, I think 9-5s are the worst thing I could ever have to do and I thank God I can do something else. I also feel like near 100% I know who work a 9-5 are not fulfilled at all and just work because something has to pay the mortgage and put food on the table. Fuck that - go on an adventure, life is too short with too many unknowns to waste your time playing Office Space (my subjective opinion of course).
I’ll end with this thought: if your heart isn’t in something (especially flying professionally), then don’t do it. Flying is not “just a job,” like a 9-5 could be. If you’re still passionate about it after a gut check, then press forward, but if not, then maybe you are just the 9-5 type…and that’s not wrong, just not for me.