Before a test

Please would someone correct my writing to natural conversational English?

I have a test and a presentation tomorrow at school. The test should would be not too hard, because I had already taken almost the same a similar class in my country. However, the presentation is a problem for me. It is already enough difficult enough trying to speak English in a proper accent, using correct grammar and intonation in front of native English speaker. So it is obviously overwhelming for me to speak English on a specific purpose to inform some knowledge. I am sure I'm will be going to be into a panic mode before the presentation. or "I am sure I will be panicking before the presentation".

Before a test

I have a test and a presentation tomorrow at school. The test would should not be not too hard, because I had already taken took almost the same class [see note] in my country. However, the presentation is a problem for me. It is enough difficult enough to speak English in with the proper accent, grammar and intonation in front of native English speakers. So it is obviously overwhelming to speak English on a with the specific purpose to inform some knowledge of imparting/sharing knowledge. I'm sure I'm going to be into panic panicking before presenting.

*Note: Because you want to correct this to natural, conversational English, I think this sounds fine as a native speaker. However, if I were writing this, I would be more likely to say "...because I already took a very similar class in my country." 

Before a test

Please would someone correct my writing to natural conversational English?

I have a test and a presentation tomorrow at school. The test would won't be not too hard, because I had have already taken a similar almost the same class in my country. However, the presentation is a problem for me. It is enough difficult enough to speak English correctly in proper accent, grammar and intonation in front of native English speakers. So it is obviously overwhelming to speak English on a specific topic purpose to impart inform some knowledge. I'm sure I'm going to be into in a panic before my presentation. presenting.