First I'd like to say congratulations, you got her. This is a task that many have tried and many have failed at, so feel special that she chose you. But more than feeling special, feel blessed that you are getting to be a part of this amazing woman's life. Throughout all of the years I've known her, I've always known her to be strong-willed, stubborn, and a little out there. Now I'm glad there is someone else who I can share her with.
But remember, that's the thing, we're SHARING her. I know you'll want to spend every moment you can with her and I could understand why, I wouldn't want to miss out on what embarrassing thing she does next either, but she's been my best friend for years so it's a necessity I see her at last three times a day.
In all seriousness, it's important for you to remember how special this girl is to me, and how special she should be to you. There's a reason why our friendship has lasted so long and it's not because the two of us always get along. She cares, she cares more about the relationships she forms than anything else. She'll show you she cares and sometimes it'll be a bit overbearing, trust me I know from experience, but it's only because she wants the best for you and wants you to expect and accept nothing less. You've truly found someone who has a heart of gold and who wears that heart on her sleeve, don't mess that up.
I'm gonna go out on a limb and say that you might already know these things about her, well I'm here to tell you that you don't know as much as you think. Be careful with her heart because she won't tell you if you've broken it. Be careful with your words because you won't know when you've said something dumb. Appreciate everything she does for you, even all the little things she does that you will never notice.
I'm okay with sharing her with you, as long as you can follow all of my instructions and as long as you remember that I'll always be more important.