She was in 11th grade even though she was older than Dylan (who was in 12th) and that is because she was born in August. Here, in the United States, if your child is born in August (like Rachel) or September (like Dylan) you have the option to start them in school when they are still 4 but turn 5 before September 30th or you can wait until the following year and start them around their 6th Birthday. Dylan's parents started him when he was 4 and hers waited until the following year when she was almost 6.
For those of you who don't live in the US. The school year in the US starts at the end of August/beginning of September and ends at the end of May/early to mid June. I live in the part of the US where school starts the Wednesday after Labor Day (first Monday in September) and ends in mid June. But in Colorado they start at the end of August and finish up at the end of May. Dylan started at 4 (turned 5 on September 11th) years old and Rachel started at 6 years old.
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“And may you grow to be proud
Dignified and true
And do unto others
As you'd have done to you”