How do I bring up to my boyfriend (22m) that I (22f) want to be engaged soon?

My boyfriend and I have been together for 6 years now, since junior year of high school. Through the years, we’ve planned out our whole future, buying land, building a house, how many kids we want, etc. Now that he’s graduated and I’m working on my second degree, the idea of getting engaged is a lot more prevalent in my mind as I’m ready to take that next step. I’ve tried to bring this up a time or two in a light manner, but he always brushes it off saying I need to graduate first or he doesn’t have the money because it’s expensive and he just graduated.

While I agree those are both valid reasons, it breaks my heart a little each time because he is doing really well. Only 4 months after graduating he was able to buy his dream truck (30k) and put half of that down on it. That didn’t bother me at all because his old car was worn, but then today he messaged me a listing of a race snowmobile that he’s buying worth more than the price of my absolute dream ring. As for the other reason, again I already have a degree, yes I’m working on a second but feel it’s completely reasonable for me to be engaged for the last year of my program.

I just feel more and more worthless every time he goes and proves he has plenty of money for a ring, but says that’s one of the main reasons he won’t. It also hurts me even more due to the fact that I have no idea of a timeline whatsoever, I could be waiting 6 more months, or I could be waiting another 5 years which makes me feel like such a low priority and like my desired timeline isn’t as important as his. How do I talk to him about this without making it seem like an ultimatum or putting too much pressure on him? I’m considering giving him a 2 year limit in which I would even graduate, but is that reasonable and fair?