I just started learning this piece on my own. I played the trill (red circle) as A G F# G (So with the context it's G AGF#G A. Is it correct? When I listen to the videos played by professionals on youtube, the F# note all sounded a little higher pitch than mine, but it's obviously not G. They sound better than my playing. I've listened repeatedly and my ears are fine, and my keyboard is also good since this is the only place that sounds different.
Yes, the ornament, known as a turn, is executed
A-G-F#-G. Unless otherwise specified, ornaments are played within the given key signature.
For additional reassurance, of the editions on IMSLP that offer explicit notation (see below), all give
A-G-F#-G. The Barry Cooper / ABRSM edition also gives the same notation.