This is the 1284th most frequent German word.
frühe
"Frühe" means "early" in English.
In this sentence, 'frühe' is used as an adjective modifying 'Aufstehen' (the act of getting up), indicating the characteristic of being early.
Das frühe Aufstehen ist besonders an kalten Tagen schwierig.
Getting up early is particularly difficult on cold days.
Here, 'frühe' is used as part of the phrase 'frühe Morgenstunden', again as an adjective describing the morning hours, which are characterized by being early in the day.
In den frühen Morgenstunden ist die Stadt ruhig und friedlich.
During the early morning hours, the city is calm and peaceful.
In this case, 'frühe' functions as an adjective modifying 'Schuljahre' (school years), describing them as being early years in her education.