Fungus on Brassavola Nodosa
 

There appears to be a fungus on my Brassavola Nodosa. It is a round spot which is sunken and is brown and Black. There is a well defined edge and I think it is expanding. However it is on the very old growths and hasn't effected the new growth area yet. Right now I am using neem oil. Is neem oil a good fungicide? If not what other potent fungicide should I use?

haven't used neem oil, and I'm not sure how well these fungicides penetrate into leaves, but if it's just a couple of leaves i usually just lop it off than wait for it to sporulate and spread.

I cut three leaves off that had the fungus on it.
By doing that will it cause the plant to delay flowering next summer? I mean there are still 7 healthy leaves left and the ones I cut off were the old, far away from the growth leaves.

Cutting off the "rotted" sections well below the rot is an accepted part of rot control and should not hurt the plant's success at setting spike when ready. Just keep the plant watered properly as well as weak fertilizer (I prefer 125ppm Nitrogen MSU mix in RO water.) The frequency of watering is dependent on how well the mix dries down. Mine are in water lily baskets in coarse bark and thus I need to provide lots of water every three days or so. You may need something less than that if the mix is staying too wet.