A two board drift in either direction is very managable. To see if it is really a two board drift, put the inside of your sliding shoe covering the middle board on the approach. Look at and roll the ball over the second arrow from the gutter several times, checking where the inside of your sliding shoe ends. If it covers the 18th board, you have a 2 board drift right, which is nothing to worry about as long as it's consistent.
What you should be more concerned about is where you specifically stand to play your best shots, and not about how you are walking. On certain lines it should appear you are drifting right, and others it will appear you are drifting left, but it's really the drift in relation to the angle you are playing that matters. For instance, being a righty when shooting the ten pin across lane I expect my feet to end up further right than where I started, but I don't consider that a drift, since I'm planning on walking toward my target.
This is one way to look at it. Another is given by Fred Borden, who likes to think about walking straight toward the foul line on the approach and making other adjustments. If you practice either enough, both are acceptable. I've seen great bowlers with tremendous "drifts". They usually are changing their walking pattern to take advantage of specific lane conditions and will practice things like walking around ball returns to do what they think needs to be done. But for basic bowling, a two board drift isn't too bad, it may not be bad at all.