I also happen to be the tech person. But I'm not the only one. So they can still survive without me.
Alarm bells ringing here. They are probably well meaning and honest, but the potential impact in the event they're not can be horrible.
You'll want it iron clad in writing now what you'll get after a year and how it is structured.
You want to make sure it's done in a tax efficient way. There are several complications here: If they award you shares or options after a year, you either lose out on the value increase in that year, or you risk getting taxed on the different between whatever price they offer it to you at and the market value in a year. If you're putting your education on hold now, presumably you would like to gain from the potential increase in value over the coming year. Especially as most startups never reach the dizzying heights of multi-billion dollar valuations and the biggest multiples on valuation you might see might very well come in the coming year.
Depending on jurisdiction there are many ways to protect both your interests (getting part of the value increase over the coming year, and avoid excessive taxes) and theirs (making sure you don't run off after getting your shares, and ensuring you have strong reasons to stay). E.g. an option plan starting now with a "cliff" that means the first chunk doesn't vest until a year from now (though options are tax inefficient most places), or letting you buy shares now (at presumably rock bottom valuation) with some claw-back provisions if you leave before certain conditions are met.
The only way of knowing what'll be best for you is to make sure to talk to a lawyer and/or accountant versed in local tax law. Many places will be willing to give you an initial consultation for free or a low fee, and will be able to at least advice you what they think will be feasible to achieve before you need to commit to paying more to actually sort out the paperwork.
(If the current founders are not willing to work with you to get proper paper work in place, run for the hills - in that case they likely have no intention of honouring whatever they've talked to you about; if everything is above board, a proper agreement will safeguard their interests as much as yours)