Tell your SA you are not ready to accept delivery. Give them a date 5-6 months in the future when you think you'll be ready. Just do the basics for your profile like insurance and license and leave payment as cash. Hopefully they honor your 5-6 months without bugging yo but you will need to check your account occasionally to make sure a vin hasn't been assigned. If one is, just reach out and ask to delay delivery. If you never confirm a delivery date and they decide to show up and leave a car at your place, you don't pay for it and it's not yours. Tesla's problem.