The speaker sums up their eighteen years by turning each year into a person, feeling, or part of themselves. The first list gathers family and friends: a mother, a father, brothers, a sister, a best friend. The second list is darker and more tangled: a rival, fear, envy, lovers, selfishness. Then come the big single words, heart, life, love, before everything narrows to "one Me."
The numbers matter. The speaker says seven years are for loving, seven for hating, and three to keep, which leaves one for themselves. That makes love and hate almost equal forces, and only a small part is saved as something worth holding on to.
The mood is reflective and a little vulnerable. The speaker doesn't blame anyone; they simply take stock. The repeated "one" suggests how single and separate each part of a life can feel, and the ending, "A year for each," gives the poem a quiet sense of closure, as if the speaker is saying that everything and everyone has shaped who they are.