Seems like they're getting married pretty quickly, haven't they been dating for about as long the main pair? Though I guess Mayuko might not feel like she can afford to wait much longer.
It's funny how some people were complaining about honorifics in the last chapter and now the characters literally state that's just how they refer to each other.
I'm glad those 2 are planning on getting married. I think at this point a couple knows whether they want a commitment or just play around. And clearly they made that decision to settle down with each other.