She is currently a grade 10 student in Canada.

Or, "She is currently in the 10th grade in Canada."

She has been facing many challenges, such as differences in food, language barriers, and relatively higher expenses to my home country.

Or, "...higher expenses relative/compared to my home country." Or, "...expenses relatively higher to my home country." Or just, "...expenses higher than my home country." Or even just, "...expenses relatively higher (than what we are accustomed to)."

All of these have resulted into some extent of uncomfortable experiences in and after school.

Or, "All of this has resulted in some uncomfortable experiences both in and after school."

Canada is a quite diverse country, in which people from different countries work and study here.

Or, "Canada is quite a diverse country, having people from various other countries working and studying here."

I advocate for students to study abroad if they can afford the expense, because experiencing a distincfferent culture can expand their horizons and will be beneficial for them to shape a healthier living life.

1. Your culture is distinct. Pretty much all cultures are distinct. But I think you mean a culture different from one's own.
2. "Can" now modifies both "expand" and "be beneficial."

When it comes to this topic, I am thinking of my daughter.

She has been facing many challenges, such as differences in food, language barriers, and relatively higher expenses compared to my home country.

All of these have resulted [in to some extent of| in somewhat] uncomfortable experiences in and after school.

Canada is a quite diverse country, in which people from different countries work and study here.

Furthermore, teachers in this country encourage students to pursue their personal interests, while the students in my original country are often expected to share the same viewpoints in my original country.

In your original wording, it sounds like “the students” in the second half of the sentence refers to the same students as in the first half. Only when the reader reaches “in my original country” at the end of the sentence does he realize that you’re describing two different groups of students.

I advocate for students to study abroad if they can afford the expense, because experiencing a distinct culture can expand their horizons and will be beneficial for them to shape [a healthier living lifefe | healthier lives].

She is currently a tenth grade 10 student in Canada.

She has been facing many challenges, such as differences in food, language barriers, and relatively higher expenses to myhan our home country.

All of these have resulted into some extent of uncomfortable experiences in and after school.

Canada is a quite a diverse country, in which people from different countries work and study here.

I advocate for students to study abroad if they can afford the expense, because experiencing a distinct culture can expand their horizons and will be beneficial for them to shape a healthier living life.