My life-----I made a mocha

I made a mocha today. I am feeling extremely happy and excited. I plucked up the courage to ask my/the manager how to make mocha. Finally, the manager not only enthusiastically helped me by explain but also made a cup of mocha. I appreciate her. A guest ordered a cup of mocha at tonight. I made a cup of mocha to for him personally. This is my biggest harvest today.

"plucked up" is a great expression to use. -- Maybe this is British English, if Alice didn't like it.

"harvest" ? your meaning here is unclear. Perhaps you mean greatest achievement today? most fulfilling achievement today?

My life-----I made a mocha

I made a mocha today. I am feeling extremely happy and excited. I worked up the courage to ask the manager how to make a mocha. Finally, the manager not only enthusiastically helped me by explaining, but also made a cup of mocha. I appreciate her. A guest ordered a cup of mocha tonight. I made a cup of mocha for him personally (or maybe "myself"). This is my biggest harvest today.