I rergret going to our grandson's NO First Communion over 28 years ago. His teacher genuflected to the 30 or so plants on the altar, while the Tabernacle was over on a side altar. Lots of old-ladies distributing Holy Communion, lots of immodest dress, lots of loud talking, lots of hand-shaking. Ick.
I would, however, go to the family get-together afterwards, and bring a great trad gift, holy cards, holy water, brown scapular with a booklet, good trad books for the child's age, a statue of St. Michael the Archangel or the child's favorite saint. Building brides is always better than burning them.