When you say "high A", do you mean the A on the top line of the bass stave, or the A three ledger lines above it?
A little circle in string writing can have two meanings. It can be a harmonic, as previously mentioned, or it can mean play the note as an open string. (There is always a choice whether to play a note as an open string, because the same pitch can alternatively be obtained on the next string down using the finger.)
You can generally tell which meaning is intended by what note it is. To be an open string, it obviously has to be one of the pitches the instrument is tuned to - low C, G on the bottom line, D in the third space or A on the top line. To be a harmonic, it has to be one of a particular set of intervals above one of these pitches.
I must admit I can't see any reason why harmonics would be marked in a scale book. That just makes no sense. At grade 1/2, it's much more likely to mean open strings. It would still then be a bit of a mystery what the "3" means (since you obviously don't use your third finger, or any finger, on an open string), but verifying what the pitch is is the first step.