Why can't you tell her you just aren't interested in the club scene anymore and suggest a cafe or coffee shop.
Let her know up front you love and cherish her friendship but have moved on and outgrew alot of things you were interested in before.
Let her know you will always be her friend as long as she can accept you for who you are now, as a Christian.
And NEVER put a friendship before the Lord.
That cannot even be a question in our minds.
And in reality, as a Christian with a new life, you may find that you don't even enjoy her as much as before.
Blessings to you~