If you have good credit, you have options there.
Yes, definitely call and ask for a lower rate. If you've been paying on time they may not want to work with you though, as they've been getting the higher rate, there's not a real reason for them to lower it - but they sometimes do and you lose nothing at all by asking.
If they don't, look into the peer-to-peer. With high credit, you could cut your interest below half of what it is now, have a set term, pay them all off in one shot and just have the single smaller bill if you got a loan that way.
Yes, definitely call and ask for a lower rate. If you've been paying on time they may not want to work with you though, as they've been getting the higher rate, there's not a real reason for them to lower it - but they sometimes do and you lose nothing at all by asking.
If they don't, look into the peer-to-peer. With high credit, you could cut your interest below half of what it is now, have a set term, pay them all off in one shot and just have the single smaller bill if you got a loan that way.