I wouldn't even be considering the possibility at this point. You are still refining the product and figuring out how to engage+monetize. It is hard to "turn down" users, but splitting your focus will likely be a mistake until you've got the core figured out. More platforms is much more work than you will expect, especially with UI expectations being different.

You may not even need those options when it comes to growth either, depending on your space. Instragram did very well being extremely focused and waiting quite a while for other platforms.

Finally, when you do start acquiring users on other mobile platforms, be aware that they will convert at different rates! Don't depend on conversion behavior similar to iOS.