I've read this book for an undergraduate differential geometry class. It's a good primer for more advanced topics. It mainly covers curves and surfaces, not manifolds in general; this is OK, but many proofs can't be generalized and, worst of all, don't teach you anything except rote computations. Unless you have a teacher who explains the ideas behind these proofs, I wouldn't suggest this for independent learning, as it would give a bad idea of what differential geometry is about.
The exercises vary from trivial to very hard. Some are uninteresting, but there are hidden gems.
After reading this book you'll want to read more general treatments (if interested), like Lee's Introduction to Smooth Manifolds or even Spivak's first 2 volumes if you have the time.
A similar book is do Carmo's, which is also the classic standard (doesn't necessarily mean better)