Yes, it's suitable for adult BPs. Like Sauzo said, though some females can get pretty big and may eventually outgrow it.
I agree with Deborah 100% as well. Some juveniles do ok in a bigger starter enclosure, but some will lack the sense of security BPs crave and will refuse food until moved to a smaller, more secure enclosure.
My two cents: start smaller. As the snake grows, you'll have time to decide on a "forever" enclosure.