Is it okay if my wife accepts Shabbos significantly earlier than I do?


Question Continued:

She would like to light candles before my son’s bedtime so that he can watch her lighting.



Yes – as long as the candles are being lit after the time of plag hamincha (which is 1 and 1/4 seasonal hours before shkiah).


See more here:

Alter Rebbe’s Shulchan Aruch 261:5 article #173: Early Maariv