This is Monday XXX, 2017, the first day I met my three aged partners. The reason I am being here is that I registered an English class in College XXX, VOLUNTEERING: Community and Communication. Yes, Bruce, Cliff and Richard do the work voluntarily. I have never thought an English course can be taught like this, but here I am, readying to work with the team for fifteen Mondays. At first glance, I certainly doubted how this aged team can move any heavy staffs. However, in the days afterwards, they proved that I was totally wrong.
Should be “the first day THAT I meant my three aged partners”.
The second line should be “ the reason that I am here is because”, followed by “I registered FOR and English class.
“I have never thought THAT an English...” sounds better.
Readying might be better as ready instead of being in the infinitive tense.
省却 that 之后就太口语化了。