That is good growth. I feed my 2013 average 2X week, sometimes 3X. My 2013 all black male ate 3 mice yesterday. Sometimes throw in a chick. Or chunk of snake meat. As long as he shows good growth in length, not just girth, I feed heavily. When growth in length slows, I cut down on food. Really just like I feed all colubrids, just more frequent. Seems like lots of folks underfeed babies, but overfeed adults!
They eat much more in summer. My 7' 2011 male eats sporadically in fall/winter. Maybe every 10 days.