If your advisor/mentor is telling you to do it, it's because they don't believe you're ready for grad school yet. Take their advice and do a 2 year (that's usually the minimum asked for) tech job. You'll be applying against people who have done this, and they'll come in with years of experience and the ability to say 'yeah, I've worked in relative field for 3 years, here's the papers my name is on/that I wrote, and this is all the experience to back up why I want to do this grad program.' Also, if you work at a school you'd like to do your grad program at, it helps.