I don't mean to be presumptuous by second guessing your financial decisions and I totally understand your frustration with the cheaper models not being updated, but in your original post you stated you bought her a 2017 refurb for $1609.
Assuming you're in the US, you can get a brand new, quad core, base 2018 model for $1,799, a difference of only $190 for a machine that will be twice as fast, and age much more gracefully over time. If your daughter is planning to use this throughout high school (four years?), I would strongly suggest you reconsider.
If you're worried about the storage (256GB vs 512GB), think of it this way: the inconvenience of an external HDD/SSD (which can be had for as low as $50-$75 or less if you watch Slickdeals) is far less than the inconvenience of a machine that just doesn't have the raw computing power (cores/threads) to get the job done. Another way of looking at it is: If you buy her the 2018 model, it should easily last her through high school and quite possibly into college, whereas the 2017 model will feel like a dinosaur (relatively) before she's even hit her senior year (assuming she's a freshman/sophomore now). So spend another $200 today and possibly save yourself (or her) from spending another $~1200+ down the line when the 2017 model just doesn't cut it anymore.
Again, just some friendly advice, it's your money, and if there's some reason she needs the internal storage more than the processing power, or, for whatever reason, you have a budget that has to be stuck to, then you do you.
Finally, see if you can't swing your daughter an education discount, as the lower price & free (resellable) Beats headphones could make all of this arguing over the 2018 model costing more a moot point. I know high school students aren't technically covered, but honestly Apple doesn't check so... (if you're not comfortable going that route, do you have any friends/family who are students/teachers/etc?)