I direct sowed cosmos seeds in the spring and I am still seeing a lot of new sprouts coming up. You would probably be fine to go ahead and plant them.

You will have success if you plant now. Just water them each day unless it rains. They will sprout quickly and need a bit of extra water until established.

Each June, I rip out poppies and larkspur that I planted in fall for spring color. I replace them with sunburst cosmos and zinnias. I have color until frost. This year I'm going to also put some in pots to spread around different bare areas in the garden.

I discovered that planting zinnias in June or early July keeps them from getting mold.

SG

We had a huge wind storm blow thru here on Sat and blew my comos completely over, I stomped them back into the ground the best I could, they lean a little now but I think they will be just fine. But what I did notice was there are new seedlings coming up from seeds that have already matured. I didn't plant any more seeds so that must be what they are from. So, I'd say go ahead and see, then next year you'll know. That's the fun of gardening, trial and error, sometimes makes for a nice surprise.

As far as your procrastination. . . gardening will wait for you till you're ready.