I'd say that if you want to learn Rust, then this is an excellent project. I'm not convinced that if you want to learn how databases work that Rust is a better language than C: it's more complex in that the checker makes you think about lots of non-db things, and simpler in maybe a non-helpful way, in that the language provides lots of high-level facilities that it might be good to work out explicitly.
Considering that i'll have to learn C for this as well, i think going with Rust just looks more interesting.
Could I trouble you to give me an example of the second one? Something rust provides that might be better to learn the hard way?
I think that dynamically sized types make life easier in places where it might be good to figure out how to manipulate the concrete data.