My Family

There are 5 personpeople(1) in my family. M: m(2)y grandmother, my father, my mother, my younger brother and Imyself(3).
My grandfather passed away 14 years ago. I'mI was(4) so sad at that time. My grandmother is a quiet, kindly lady. She brought me up.
My father is a math teacher and my mom is a office worker. They are busy and dedicated.
My younger brother is a middle-school-student. He studies hard and enjoys(5) reading.
I do love my families and they love me too. They don't tell me but I know it.

1: person is singular, since there is more than one person, you must use "people"

2: In speech, this wouldn't make a difference... more of a written grammar thing. Sentences need a verb, so this part cannot be a standalone sentence

3: "I" is the reflexive form that performs actions: "I eat food" "Him and I eat food." When the recipient of the action is reflexive, then it should be "myself" instead. "I looked at myself" or "I cleaned myself." Colloquially, you could probably say "me" here instead of "myself", but myself is more correct.

4: "I'm" or "I am" is present tense; since this happened 14 years ago, you must use the past tense, hence "I was"

5: "enjoy": "I enjoy" "You enjoy" and "They enjoy"...but "He/she enjoys" or "John enjoys" or "Jane enjoys"

Corrected:

There are 5 people in my family: my grandmother, my father, my mother, my younger brother and myself.
My grandfather passed away 14 years ago. I was so sad at that time. My grandmother is a quiet, kindly lady. She brought me up.
My father is a math teacher and my mom is a office worker. They are busy and dedicated.
My younger brother is a middle-school-student. He studies hard and enjoys reading.
I do love my families and they love me too. They don't tell me but I know it.

You did an excellent job! I had to search extra hard cause there were very few mistakes :) Keep up the good work!!