Marisa said:

That feeling of invincibility was more like that of a child on a sugar rush.

Rather than mentioning children, the original line is actually saying (in a more literal translation) "That egoistic sense of omnipotence was like an overly sweet piece of sugar candy". I think I don't 100% get the simile, but notably, it's a play on amai meaning both "sweet" and "naive". However, I think it would be pretty incomprehensible in English, so I tried to think of a localization that would be intelligible and hopefully not too goofy while also keeping the association between sugar and naivety if possible.