A3 is a very popular note for a first crystal singing bowl. It has a beautiful low grounding tone and it is available in the smaller 13" and 14" sizes which are more affordable than the larger 16" which is needed if you want to have a bowl lower F#3 or lower. If you are looking for a bowl to go with A3, you might consider adding D4 for grounding tones (Perfect 4th), E4 for total relaxation (Perfect 5th) or F#4 for expanding tones (Major 6th).
Not sure what note is the lowest in the third octave?
This is the order of the crystal singing bowls, lowest to highest in the third octave.C3, C#3, D3, D#3, E3, F3, F#3, G3, G#3, A3, A#3, B3