If you're already working as an engr/scientist, the best motivation for a graduate degree would be to contribute something 'new' to the field and/or expand your skills so you get better at the job you're already doing. A grad degree may or may not result in more opportunities or better pay - and if these last two are your motivation, you probably shouldn't get a grad degree in CS. Getting ahead or earning more has very little to do with your IQ and probably a lot more to do with your EQ... I've seen brilliant folk get masters and PhD even in CS, an MBA, even JD... only to end up disenchanted because they start out with the wrong motivation and the outcome doesn't match their expectations.
Examining your motivations is not easy and should be done with someone that knows you well, isn't family and can offer objective/'cold' advice. If they fail to dissuade you w/some real life experiences and you are still fired up, then you should probably go for. it.
TLDR do not embark on a major undertaking without due process (or self process, as it may be).
Trust me, I've 20 years of software engineering exp and an undergrad in CS.