I can't say for certain if it was a generic email but it doesn't sound like it since it mentions specifics around your GRE Quant score and years of experience. <15% of their MPAs have under two years of professional experience (from their Viewbook) and I believe they accept few, if any, directly out of undergrad. You can also see their Quant score breakdown in the viewbook: https://spia.princeton.edu/graduate-admissions/graduate-viewbook
Since you received full tuition from SAIS, if you're very interested in their program, it sounds like you have a solid option. I personally am grateful for my years of work experience between undergrad and applying to grad school, though, so you may find value in waiting a view years (especially if you were heavily invested in attending SPIA). It seems like you can't go wrong -- it just depends on your values!