Sexing discus is quite difficult at the best of times. Occasionally, you may find that while females generally have a dorsal fin that is smooth, even and rounded at the back end, while SOME males' dorsal MAY end with an arced, pointed tip at the end - but that's said not to be a very reliable indicator.
Your two fish both appear to have rounded dorsal ends, but that's not evidence they are both females.
Another indicator (IF you can spot it while the egg-laying is taking place)is that the female may have & show a rounded anal tube/protrusion, whereas a male's is tapered to a point.
Keep an eye on them - they'll spawn again - when they do, and if you have a male, he may fertilize the eggs (many times, they don't, particularly when they're new at it - sometimes it takes several spawnings for them to "get it right").
Healthy, fertilized eggs will take on a light brownish color, so you'll know.
As/when you get a couple more spawnings, if the eggs stay white, you'll know you have 2 females.
Hope this helps.
Check out the very first picture in an album of mine below:
That first pic is of a Red Snake Skin believed to be a male - see how the dorsal fin kind of sweeps up/arcs into a pointed tip at the end.
P.S. In Pic # 9 - center of tank - the 2 RSS's -.....left one is female - right one is the believed male (You can also see the 'male' in pic #12) -(click on photos to enlarge)