I would get the BSN first. If you're in the school and it's there, do it and get it over with.
I'm going the ASN-->BSN route because 1. I already hold a BA from 12 years ago so I didn't feel a rush to get the BSN; 2. the ASN is the more affordable option right now; 3. I'm almost already finished with the ASN program and haven't even been formerly admitted--all I have left to take are the nursing classes themselves; and 4. I got a D in organic as an undergrad so to get ready for a BSN program would take me another year as I retake the course plus physics
I do plan to get a BSN at one point. I would have done an accelerated BSN program if it weren't for reason #4 above.
If I could have done it differently all those years ago, I'd have gotten the BSN the first time around. Then again, when I was an undergrad the first time around, I wasn't sure I wanted to be a nurse!