Is this trilogy OK for younger children to watch?

I'm a bit late but yeah its suitable for younger children.

The Gamera trilogy films can be very violent and disturbing at times, but overall they should be fine for young children. A good deal of the graphic violence is restricted to the monsters, and most of the darker themes (which mostly exist in the third film) should go over young children's heads. The first and second films are probably more appropriate for children than the third film, which contains much more graphic violence and frightening imagery in addition to a brief scene with somewhat sexual innuendo. The Gamera films have traditionally included a lot of graphic monster violence despite being aimed towards children.