This is much earlier than a normal employee. I'd say this is about right, although you should be considered a founding team member and not an employee.
Thanks so much! So apart from the issue of founder v. employee, you think this is a reasonable situation? I think the founders are happy to bring me in because I'm generally competent/capable (and we've been friends for 10-15 years, they know I'm reliable), but again, they are the ones with all the industry knowledge.
I've had some people pressing me to push for founder status, but I think that's a bit much.
The offer is clearly more like a founder in that you are agreeing to a significantly below market salary in exchange for a pretty sizable chunk of equity. So whether the "title" of co-founder is given or not, they are treating it more like a minor partner/founder.
Given that this offer is equity heavy - you should understand things like vesting schedule, and dilution when additional investment comes in.
I've had some people pressing me to push for founder status, but I think that's a bit much.