My speech for class

Hey all :)
Please help me translate some sentences. It's hard to find an example of a Japanese speech online.

How would one start a polite formal speech? To a Student body?

Like 'I'm honored to be here, to be a representative of America'''
''Just two weeks ago, I volunteered at a Akido competition.'
'I have always been fascinated by Japanese culture, and have been a fan of anime and manga since the young age of 5'
'I really like how Japanese people respect each other in every form of culture, like arts or sports'
'I took up Akido because I love the aspect where one teaches and discplines one's heart, while training one's body'

And also how would one end a speech?
'That concludes my speech and I hope you enjoyed it'

yoroshiku onegaishimasu!

For a start, avoid the use of the abbreviation "Jap" in any situation. You might not be aware that it was a derogatory term for Japanese during World War 2, and is still considered offensive.

I'm sure you were just trying to fit your title in, but you should just avoid it completely.

Avoid JAP but it doesn't actually appear in your speech so thats fine.

Well one thing you should do is start the speech by actually introducing yourself?

Watashi-wa your name /desu or -to moshimasu depending on how formal you want to be.

Wouldn't an appropriate start be
"Hajimemashite" ?

I agree that you should first introduce yourself. You should also say where you are coming from (university or school, town, state.) saying you are a representative of America is redundant and wrong as America is more than the USA. Try not to use stereotypes.

The martial art is actually "Aikido", with an "i" after the A and the first syllable "Ai" sounding like "eye" in English. If you mispronounce it they may not understand what it is you are practicing.

First Japenese will always use thier good maners when meeting someone,what you need to do introduce your self where you came from and what is your purpose in Japan, avoid using derogatory stereotype Japanese are also easy to get offended if you not careful with your sentence.

apologise for your poor japanese (even if it isnt) and tell them that you are only a beginner at Japanese and aikido (even if you arent - keep in mind that there are many 17 year old nidans and sandans here!!).
Be severely modest in every thing you say!!!
Tell them you LOVE Japan, how beautiful Japan is and how much you admire Japanese culture!!

saying you are a representative of America is redundant and wrong as America is more than the USA.

This is incorrect. In Japan, America (アメリカ) refers specifically to the USA, and is perfectly acceptable to use in this way.

If, however, you want to say you are from North America you could say you are from Kitaamerica or Kitabei, but it would be better and less confusing to just say the country, i.e. Canada or Mexico.

Also, I'm not sure why it would be redundant especially as it is the first sentence in your speech.

Sorry for being rude with my question. Does anyone know how to translate, "I wish to learn Aikido by watching others in an Aikido competition" ? The only reason I use "representative" is because it's a contest I'm in. And really thank you for your replies