I’ve read elsewhere that, “A bird is hand is worth two is the bush.” If the current circumstances are not particularly unfavorable, there are apparently no reasons to wait for some future time (after 3 years), when the situation can’t be necessarily predicted. However, any sort of making haste may be a bit too pushy while your partner is clearly not ready for marriage immediately.
If currently there is no pressing need to get married, a bit of waiting could make sense. A few weeks of not being too worried about whats coming in future should allow you some space and time. You can always go back to the problem with a fresh outlook and see how to take things forward from there. Good luck!