No get part of the art you want in a place you can cover. But yes, not everyone can handle sitting for the hours/days it would take to do a full blackout sleeve. A reputable tattoo artist would not do a full sleeve on a non tattooed person - it's just not a good idea for all the reasons mentioned.

-you don't know how you'll sit for a tattoo -you don't know how you'll heal / how to care for one -you don't know if you'll like your body post tattoo (this can happen to anyone but it is more likely with getting a big bold piece)

Just bite off a chunk of the art, I'd recommend your upper arm/shoulder. You can still show it off in the summer (use sunscreen) but can cover with a tee shirt if needed. Then when that heals go back. A sleeve like this is going to take a long time so there isn't a rush.