For anyone already thinking about taxes as they relate to the NSF GRF, here are some key facts and resources that I have found helpful over the past two years (especially last year when I was on tenure for the entire calendar year).
The stipend fellows receive from the NSF GRF is considered "taxable income," but it is not considered "taxable compensation" by the IRS. Basically, what this means is that you have to pay income taxes on your stipend each year, but you cannot use your stipend to contribute to traditional or Roth IRAs.
Your university will also not include stipend payments on your W-2 (assuming they're following the rules), and your university may not be able to withhold taxes from your stipend payments. In this situation, you either have to pay several thousand dollars at once when taxes are due (including ~$70 of interest on "late" payments), or you can make "estimated tax payments" quarterly to split this up more evenly and avoid the interest fee.
If you do a Google search, it seems there used to be some ambiguity surrounding taxes and fellowships, but it appears the IRS has made their policies rather explicit within the past few years. This page (https://www.irs.gov/taxtopics/tc421) talks about which portions of fellowships are considered "taxable income" and how to report this income on your 1040, and this page (https://www.irs.gov/publications/p590a) talks about what kinds of income can be contributed to traditional and Roth IRAs . (The key sentence on the second page is, "Scholarship and fellowship payments are compensation for IRA purposes only if shown in box 1 of Form W-2.")
For what it's worth, Congress is aware of the problem of fellows not being allowed to contribute to retirement accounts. Last year, Senators Elizabeth Warren, Mike Lee, Ron Wyden, and Tim Scott introduced a bipartisan bill to fix this problem (https://www.warren.senate.gov/newsroom/press-releases/sens-warren-lee-wyden-scott-introduce-bipartisan-bill-to-help-graduate-students-build-retirement-savings), but (as far as I'm aware), it was never voted upon, and this issue was not addressed in the tax reform bill passed recently. (Please correct me if I'm wrong.) This standalone bill was first introduced in 2016, and I suspect it will be reintroduced again later this year (if it hasn't been already).
I would say it does on an interpersonal/social level. Like OP I am first gen for both grad and undergrad. I'm still trying to explain to my family what a PhD even is, what I do in a program, what types of jobs I'll be able to get with one that I wouldn't have been with just a BA. Fortunately I have no actual language barrier, but talking about grad school, PhD programs especially, just requires a totally different vocabulary that isn't a hurdle for people whose parents have also gone through the process themselves. Maybe on the day to day there is no insider advantage but I definitely think there is socially/interpersonally.
