I didn't want to call it an advanced introduction, at the risk of sounding absurd.
What I'm looking for is a mature and/or modern introduction to differential geometry. Let me clarify three things: what I mean by mature is that the book should assume (or at least be targeted towards) someone who has experience reading math, and say a solid background in analysis, topology, and algebra (and maybe a very basic intro to differential geometry). What I mean by modern is that it does not shy away from using modern algebraic and analytic machinery. What I mean by "and/or" is that of course, I would be interested in either modern introductions or mature introductions, due to fear that maybe both is a tall order.
I know do Carmo has "Differential Geometry of Curves and Surfaces." Is that the best choice?
Although it's not exclusively targeted to a "mature audience", I think Lawrence Conlon's book Differentiable Manifolds meets your other criteria (especially about using modern algebra) and is well-written and quite detailed.