Your plant will probably get to blooming size next year so I wouldn't trash it now! Also, it won't bloom well (or at all) if the root was planted too deeply. In fall, you can gently scrape away some soil & check how deep the "eyes" (which look like reddish-pink buds - these are where the stems grow from in spring) on the root are. The eyes should only be 1-2 inches AT MOST below ground level. If it's too deep, this fall I would either remove some soil, or dig up the root & replant it to the proper level.
The spots are probably a fungal disease - I forget the name-and is common on peonies in wet/humid weather (kind of like blackspot affects roses), it doesn't kill them. But make sure you cut off & throw away all of the above-ground plant in fall to prevent it from returning next year.

Don't give up on the plant yet. It is considered a young plant still. Give it more time but I agree with the above post to check if the eyes are only 1" to 2" below the soil level. I would scrape around the base of the plant to check the eye depth. Next year you will probably see some flowers then the year after that even more flowers. It will mature to give you the flower count you are looking for. I use bonemeal scratched into the top 2" of soil in fall & in early spring again. I keep the bonemeal away from the eyes though. I go out about 6" away from the eyes. I need to do that with my soil but other than that I don't even fertilize my peonies.