Here you go! Although this links to a Reed page, it lists the undergrad colleges sending the most students on to PhD programs in several fields and overall. Grinnell looks amazing on these lists!
https://www.reed.edu/ir/phd.html
Grinnell also has better resources than almost any college in the nation. It ranks 11th on the per-student endowment, higher than some of the Ivy League colleges:
https://www.■■■■■■■■■■■■■■■■■/college-rankings/details/EndowmentPerStudent
So, if your mother wants you to attend a college with among the nation’s best resources for undergraduates and with among the best reputations at graduate schools, Grinnell is a great choice!