is this a good opening
At our level, openings hardly matter. It's mostly a matter of reaching an equal middlegame and being comfortable (ie knowing your break moves, basic ideas behind the opening).
From what i know about openings, it seems to me like black has equalized here at least, but no glaring tactical or positional disadvantages exist.
Much stronger than the erroneous placement of the dark square bishop on a3 would be g3 and Bg2 as in a typical KIA setup. But for very fast games (2 minutes and under) it might not be too bad, since the quality of play is lower and opening mistakes are therefore less important. It's up to you.
I think its good for blitz games, but not in a serious match. Black can answer g6, Bg7, 0-0, Re8, e5, I believe this should be the main idea, inspired from facing benko, where black sacrifies a pawn to place a bishop on a6 and white cant play instantly e4. In our case, black cant play e5, its almost the same.
1. Nf3 2. b3 has been played by kramnik and some other top gms, although not necessarily with Ba3. it sometimes transposes into a type of english opening. Ba3 with the thought of preventing castling doesn't really work as you might think, as black can fianchetto his dark square bishop and not have any problems. don't listen to anyone here who discounts you so quickly. try it out and if you get crushed its time to move on but if it works keep at it- your rating might go up, and you'll play better players, and eventually you'll probably start getting crushed again, but hey then you can try something new.
I have played this opening otb [believe it or not] with the same position as white after Ba3.
Since I lost in 20 moves with my king mated in the centre I have to answer "No". Might be great for Schiller's next UCO though.