Default window size of Acrobat App

Hi, I use Adobe Acrobat Reader DC every day. Whenever I launch a first PDF document on my Mac, the Acrobat reader opens but as a tiny little window. I need too manually resize that window if I want to see it larger - fitting my screen. Now this issue happens only with first document being opened, when I open another document, the document opens as a new tab in the window... this is fine and I'm not talking about the size of the document or viewing options of the document but about the size of the window of the Acrobat App. Is there a way to fix this setting whenever the app is launched with it's first document? I already reinstalled Acrobat Reader but it did not solve the issue.  attaching example of the small window size upon opening a file on my mac. Thanks.