R.J.
Not only does she sound right on track/ahead....
BILINGUAL kids are nearly always a whole year or so "behind" ;) single language speakers, and then at around ages 3-5 are completely fluent in BOTH. Age 2-3 is the notorious sentences of mixed origins. So half spanish/half english... or all english but with korean grammar & vice versa.... or half french half japanese but with the grammer split 1/2 and 1/2 too... or all one language, but in the "accent" of the other. And then poof! Their minds separate the two out literally overnight, and they're chattering away like magpies. Tri & quadralingual + households the timeline is ABOUT the same as bilingual. Children's brains are amazing.