not too early, good to be ready in cases of emergency. for baby i only packed clothes & mittens, swaddle. for myself, i packed pads, toiletries, disposable undies, cardigan, socks, going home outfit, chargers. try to research more and see what you might need/ not need :-)
I've had it ready since 34 weeks hehe. I think at 36 you're almost full term and could happen anytime after 37 weeks so will be a good load off of you have it handy.