Congrats on getting the boat ready for sailing.
Do not know about you, but is always feels it takes way longer to get to the water then it did when I started the projects... Then you are on the water and you start looking at more ways to work on the boat.
Sails are the power source for a sail boat. So it is only natural to see them as an upgrade spot.
If I read your story correctly you are at the least seeking an outside (possible professional) opinion on the status of your main sail that you think is original equipment (as
@dlochner identifies 30plus years) but not used much by previous owner.
Being a project loving guy with a 1974 vintage boat, I think I can relate. My sails were original vintage.
My suggestion. Unless you plan on competing in the 222 ODay class races (not even sure they exist). Recognize you’ll be chasing the latest and greatest sails and gear in the competing world. Kind of like the amateur golfer can not wait to see the new golf clubs that debut right before the season begins.
I would spend some sailing time getting to know your new to you larger boat. Sail the hull out of her. As you have already know many of us are either collectors (have more than one boat on the property or at a marina) or transition boat owners (this is my boat, until I go to the boat show and see what I can get for just a foot or two bigger boat).
If racing is in your blood and you have been bitten by the passion, then by all means buy a new sail. It may yield you a few more spots up in the pack. Then take lessons. These will be the best money spent.
If money is the driving force, then conserve the boat bucks till you are ready and maybe need to spend it on a new sail. Note that sails while important are not a big factor in the eyes of the person who is about to buy your old boat when you are ready to transition. They are a bit like the tires on our car. You spend $500 for new tires then try to sell the car and they may help with the sale but your not getting $500 more for the car.
Then there is I want a new sail, I have the money for a new sail. I got a new sail. Who can argue with that. It is your boat and your choice....