Here is what we have from the Years of the Trees:
1169 Birth of Fëanor
1170 Death of Míriel ( 3 )
1185 Marriage of Finwë and Indis ( 4 )
1190 Birth of Fingolfin ( 1 )
1200 Birth of Lúthien ( 2 )
1230 Birth of Finarfin ( 1 )
1250 Dwarves enter Beleriand. Fëanor creates a new alphabet for the Elves. ( 1, 2 )
1280 Marriage of Finarfin and Eärwen ( 1 )
1300 Thingol builds Menegroth. Daeron invents the Runes. Birth of Turgon and of Finrod.
1330 Orcs enter Beleriand
1350 Nandor enter Beleriand ( 2 )
1362 Births of Aredhel and of Galadriel ( 5 )
1400 Melkor released ( 2 )
1449 Fëanor begins work on the Silmarils
1450 Fëanor completes the Silmarils
Note that Fingolfin is born 5 years after the marriage of his parents, and that there is 40 year gap between Fingolfin and Finarfin ( who do have 2-3 sisters in some versions of the story).
Finrod's father is 50 when he marries. Finrod is born 20 years after the marriage of his parents, and then his youngest sister Galadriel is born 62 years later. There are at least two brother between them.
Turgon is also 62 years older than his younger sister Aredhel. His father Fingolfin is 110 when he is born. He has an older brother (Fingon), and we don't know when their parents married.
So... if Fëanor and Nerdanel married when Fëanor was 51, it would have been in the year 1220. We know Maedhros is younger than Fingolfin, but not the correlation of the ages of any of the Fëanoreans to any of their half-cousins. Fëanor and Nerdanel were likely finished raising children before he started on the Silmarils.
Here's a guess at birth years for the Fëanoreans:
Maedhros: 1225-1240
Maglor: 1245-1260
Celegorm: 1265-1280
Caranthir: 1285-1300
Curufin: 1305-1320
Amrod and Amras: 1325-1340
Note: There is at least one list of their names that puts Curufin as older than Caranthir, but this is the more typical order.
In other words, Curufin is likely a little younger than Turgon and Finrod. So, it's possible that Curufin was getting married roughly around the time that Galadriel was born, making Celebrimbor potentially born not that long after Galadriel. But Celebrimbor is almost definitely younger than Galadriel. The YT 1374 estimate is likely in the correct ball park.
I guess this show is going with the 'it's not the years, it's the mileage' interpretation of aging....