If she is truly your best friend, you're making the right decision. I've been only married for nearly 2 years now and the first year was definitely an adjustment. We had a lot of fun but definitely had our fair share of disagreements. But after year 1, something seemed to have clicked. Everyone says that but now that I've been through it, I can actually agree. Year 2 has been a lot more smoother and because I did marry my best friend, I have zero regrets!
GL my man and congratulations!