Wow, I'm impressed. I don't know you well or how much you ride but from my perspective that sounds great! I just did my first ever group ride/event yesterday which had some mild rolling hills and was 30 miles. My average speed was just over 11 mph. So you did great!
Have you cycled that distance before? Often? All I can say is that you are an encouragement to me. I found my ride to be very challenging. Good for you and keep it up.