please use an exciting, attention-grabbing first sentence about this significant person. Avoid the use of a passive verb like “is”. Most good writers will find that boring. I could help you with more specific examples if you had written a little about the kind of person you consider most significant. Also, next time, please include your grade level or college level in your question.

Here are a few examples:

“In my neighborhood, most high school graduates settle down early, marrying a farmer or finding work in town, but thanks to my uncle Joe, my life took a completely different turn. Against the wishes and opinions of so many others in my life, he encouraged me to follow my dream to study photography and journalism. Now I find myself in my first year of college and am so grateful to him.”

or perhaps

“Growing up in a single-parent home made my life difficult from beginning on. I worked a lot, fought against so many emotional problems brought on by the situation, felt different from my friends and questioned my own value and the possibility of a bright future. Without Magdalena I might have never believed in myself.

Try something along those lines. Perhaps the pattern fits for your significant person.