OP I'm 24 and my girlfriend is 25. I just thought I'd give you some of my own experience.
I want to marry my girlfriend bad, like real bad. I want to never introduce her as my girlfriend again. It's become insulting to me I feel from a purely "social" sense. I want people to know I took that extra step with her from a "social" sense. I want to show all of my friends and family that I love this girl so much I just can't bare to not have the strongest label on it possible.
It's been close to 7 years now me and my girlfriend have been together. My urge to get married really came about 2 years ago and it's been slowly growing in size. I think about it at this point nearly every single day.
But I also know that there are things that may be more important than that. Such as knowing that I have a large enough savings to actually make a commitment that I can be the best man possible in. That means having enough security for me and my would be wife.
I know that while the title would be amazing to have I only reflect on that from a socially conditioned point of view.
That deep down at the end of the day what's actually important is simply that you love and cherish the person you are with regardless of what your title is.
That being said if you feel you need the title in order to progress your relationship and personal development I urge you to consider this.
It may not have the same effect on you that it has on your partner for starters. But more importantly plenty of people who get married don't take a step forward on those levels or simply don't work out.
The idea you may have is simply a social construct that doesn't actually alter your relationship.
It in fact only causes you to change the way you view your relationship which can then in turn alter you and your partners actions and create new dynamics.
I suggest you tell him exactly what you told us. You decide how important having an epic party, wearing cool (superficial?) rings, and being legally attached is.
5 years in my experience isn't an unfair amount of time to spend waiting for marriage. You've been with him most of your young adult life. Take that into consideration.
If the idea of not getting married is a deal breaker for you maybe you aren't with the right guy. It's about the mutually exclusive lives you share with each other and how you each push to help the other achieve your definition of success.
In my experience I try not to talk about marriage with my girlfriend. When I do I feel like I'm teasing something I honestly just can't afford yet.
You should find out your boyfriends feelings and really hash it out with him. Good luck.