User blog comment:ReverseZoom101/Did Barry go to a different Earth before he came to E-3 (Supergirl)?/@comment-27700324-20160419164635

The reason why he asked about the superheroes on his earth is because he was going to Earth 2. When he asked Kara about firestorm, she never heard of him, he probably suspected that he was at his destination until he asked about Zoom. Kara said she never heard of him, he realized he was on the wrong earth.

It was not about his past experience in the multiverse, we would have seen those other earths if that were the case.