Rossolimo Attack (Almost) Gone Wrong

I recently started playing the Rossolimo Attack in response to the old Sicilian. I think my game started out quite good, even though I was not familiar with the move 4. Nf6. However, at some point I started going wrong. Apparently I should have tried a pawn push 15. e6 instead of 15. Nc4 and I kind of see why but I am not sure if I fully get why my plan was not that good. From this move on my position got steadily worse and I was lucky my opponent missed the checkmate in the end (That this was possible kind of seems like a hint to me that my plan was not complete trash).

Any input: thoughts, ideas, advice, etc is welcome!

I am no expert on the Rossolimo but I think people take on C6 immediately, not even castling.

You were doing well. 24 h5 is bad: the pawn will later come under attack there.
26 Nf3 27 Nh4 puts the knight on the rim. You still could support pawn h5 with 26 g4.
28 Na4 puts another knight on the rim and loses pawn h5. 28 Ng6 was possible. This whole knight maneuvre will cost you pawn a5.
If he defends his back rank 41...Ra8 it would have gone wrong indeed.

You can't post in the forums yet. Play some games!