Theory:

I would look up into your eyes,
and all the love I would see.
How did I get so lucky,
you were the dad chosen for me.
Explanation:
 
The speaker says that she would be able to see the love in the eyes of her special hero. She could see all his love when she looks up into his eyes.
 
shutterstock_1800115441.jpg
The speaker could see love in the eyes of her special hero

One could observe that the speaker had placed a lot of emphasis on the love expressed by her special hero. Love seems to be the most cherished attribute of the person. Also, it was the love that made her feel safe in his arms.

As the poem progresses, we learn that the special hero is none other than the speaker's father. She says that she feels so lucky to have him as a dad. She writes, "how did I get so lucky, you were the dad chosen for me."
 
Collage 1.jpg
The dad looks at her daughter with love (top); the girl sees her father as a hero (bottom)

As humans, we are bestowed with so many powers; one can get almost anything in the world, as long as we have sufficient money or know the ways to earn it. However, nothing can make one feel complete without love. To the speaker, it was not merely the father, but rather a father who could love her absolutely, that made her feel lucky. As Oscar Wilde had once said, "who, being loved, is poor?"* The unconditional love and care from the father had probably made her childhood worth remembering.
 
Meanings of difficult words (from the explanation):
 
S.No
Words
Meanings
1
EmphasisThe particular importance or attention that is given to something
2
AttributeA quality or characteristic that someone or something has
3
Cherish To hold dear
4
UnconditionalComplete and not limited in any way
Reference:
State Council of Educational Research and Training (2019). Term-3 English Standard-8. Special Hero - Christina M Kerschen (pp. 104). Published by the Tamil Nadu Textbook and Educational Services Corporation.
 
* http://www.literaturepage.com/read/woman-of-no-importance-69.html#:~:text=But%20we%20are%20very%20poor,Oh%2C%20no%20one.