It might make sense to read a translation in a language you understand. Many of the books that are considered classics are specifically because they ARE accessible. That doesn't necessarily mean that they are easy, but there is a big difference between reading Euclid and learning how to create mathematical proofs, and taking a class focused on calculating the area of various shapes or determine angles.
I haven't read Mathematical Principles of Natural Philosophy (the English title) but I have read Euclid and it definitely doesn't require a genius to understand. here is an online edition with great illustrations:
From what I've heard, Euclid is fairly accessible and was for centuries the standard geometry textbook for children; the Principia is incredibly daunting, and Newton even admitted that he made it extra confusing on purpose to deter readers who weren't already experts.
I haven't read Mathematical Principles of Natural Philosophy (the English title) but I have read Euclid and it definitely doesn't require a genius to understand. here is an online edition with great illustrations:
https://www.c82.net/euclid/