Aight so here's the deal.
The bottom line is that your lucky she's trying to give you a Honda.
Regardless of which car you pick, you'll have a Honda, and if you treat it well, she will give you many miles.
Of course a civic is an EXCELLENT first car (in my opinion), and I woulda LOVED to have one as my first. But from my experience, if your mom wants to give you her CRV, you can't go wrong with that, and you won't have any payments (I assume you're not taking over (if any)), and you also won't have to save a few grand to buy a civic all while being on foot.
In my honest opinion, I think you should take the CR-V.
In the meantime, if you still wanna drive around a nice lil civic, you can save your money (since I'm assuming you won't be making payments) all while you have a great and dependable car to take you where you need to go.
Conclusively, a civic is a better "first" car, but hey YOU CAN GET A FREE CR-V!! Just take it!!
Chances are, if you save your money, you'll have a better opportunity at buying THE CAR YOU WANT.
Best of luck with your final decision