If it's a laminated blade you should have no issue with the outer sides. The centre may cause issues. My advice would be to mix it up (assuming you don't have solid carbide bits) and drill with a normal metal drill bit until you have issues then switch to a masonry bit....for a bit.... then back to the metal bit. If you're not careful you can melt off the end of the masonry bit but I treat them as disposable. You may also find that pecking at the steel helps as opposed to just hanging off the handle and putting all your weight on it.
Another trick you can try is a square pointed centre punch at the point where you're struggling. It will reshape the hole and give the bit a different shape to bite into.