The oracle-bone 我 was not a person at all: it was a weapon, a long shaft tipped with a saw-toothed blade, used in Shang-era sacrifice and war. Because the weapon's name happened to sound like the word for "I", scribes borrowed its picture wholesale to write the pronoun — the blade was forgotten, and only the self remained.
A piece of culture
The word only an emperor could say Classical Chinese once had a whole crowd of words for "I" — 吾, 余, 予, 朕, 我 among them — and anyone could use any of them, emperors and farmers alike. That changed in 221 BCE: the same year the king of Qin crowned himself 皇帝 (as you learned at 王), he also decreed that 朕 (zhèn) was now his alone to say — a title reserved for the emperor, forbidden to everyone else. Commoners were left with the others — and of that whole crowd, 我 is the one word that survived into modern Mandarin as everyone's "I".
Use it in a real word
我家
wǒjiā · ngo5 gaa1
my home; my family — literally "I home"; you already know 家