I was about to be late for school, event though today is the begingning of Uthe university’s semester lol. I was about to be late for school, even though today is the beginning of the university’s semester lol.

I was about togoing to be late for school, event though today iwas the binging of University’sfirst day of my semester at uni, lol. I was going to be late for school, even though today was the first day of my semester at uni, lol.

Since you used "lol", which is slang, I changed "University" to "Uni" to match the tone of your sentence. (uni is short for university)

I was about to be late for the school event, though today is the binging of University’s semester lol. I was about to be late for the school event, though today is the binging of University’s semester.

Grammar

I'm glad to see my friends infor the first time in a while. I'm glad to see my friends for the first time in a while.

I was glad to see my friends infor the first time in a while. I was glad to see my friends for the first time in a while.

Inconsistent tenses

I'm glad to see my friends in the first time in a while. I'm glad to see my friends in the first time in a while.

Beginning of the semester Beginning of the semester