My boyfriend and I lived in a van for a few months while traveling around Colorado. Now we live in a 720 1 bedroom apartment and we're considering downsizing to a studio because we just don't use that much space - even considering our two big dogs.
Living in a small space made us be more mindful of our possessions and of keeping our space clean and organized - because we had to. It also made it easier to refuse unnecessary purchases because we simply didn't have the space for it, and we didn't feel like we needed to fill unnecessary empty spaces. We're still mindful about the things we purchase because we know we're going to go back to traveling in our van as soon as possible, so if we won't use it in our van, and there's no point in owning it for less than 2 years, we won't buy it.
If you're considering downsizing, maybe consider renting a small apartment for a few months or a year just to see if the size feels cozy or confining before committing to a tiny home. While this might help you adjust to the size, the rent should also be cheaper than your current rent/mortgage which would help you build up your savings for your deposit for your new not-so-tiny-tiny-home!