Yes, the differences between standard German in Austria and Germany are not very big, whether you learn German in Austria or Germany does not matter.

Hi Aditi! The dialects in Germany and Austria can vary lot but we all learn and have to use High German in School. Once you are in areas that speak German you´ll be able to tune your ears in. And everybody who speaks a dialect can tone it down so understanding each other is possible. It´s fun, actually, and a lot of Germans, Austrians and Swiss constantly guess where other people might be from, according to their dialects and accents. With Dutch and Flemish I have no experience. Greets, Franziska

Hello Aditi, the answer depends on your goals for learning German or High German. If you want to work or study in Germany, or you need a DELE, etc., then I would recommend Germany for learning High German.