When I was in middle school my English teacher tried to toughteach me the English language, especially the American accent, however, his classes were boring and I didn't learn much.

You’ve used “tried” in the past tense, therefore you can use “teach” in the present tense as we already know you are talking about a past experience

When I enterstarted high school my new eEnglish teacher showed me the British accent and I immediately fell in love with the English language.

More common usage (started)
English is a name of a language = proper now = capital letter

Before knowing aboutdiscovering the British accent I used to think that English was the most awful language on earth, then I discovered the bBritish accent and I got really got interested into it and I even started learning English in my free time by myself.

Discovering is more appropriate here

I didn't know what to answersay.

More common

Due to that little talk that we had made meI realized that I still love the British accent.

"I always finish what I start" It'is a promise that I didmade to myself and is a mantra that I say to myself when I want to give up.

If I started learning the bBritish accent, I'll keep learning English until my British accent and pronunciation becomes perfect.

British is a proper noun (grammar)
“Are you British?”

When I was in middle school my English teacher tried to toughteach me the English language, specifically the American accent, however, his classes were boring and I didn't learn much.

When I entered high school my new english teacher showintroduced me to the British accent and I immediately fell in love with the English language.

Before knowing about the British accent I used to think that English was the most awful language on earth, then when I discovered the british accent and I, I became really got interested into it and I even started learning English in my freetime by myself.

Right now my accent isounds more American than British.

Due to thatThe little talk that we had made me realized that I still love the British accent.

"I'll always finish what I start" It'is a promise that I didmade to myself and is a mantra that I saytell to myself when I wanever I'm about to give up.

If I started learning the british accent, I'll keep learning English until my British accent and pronunciation becomes perfect.

When I was in middle school my English teacher tried to toughteach me the English language, specifically the American accent, however, his classes were boring and I didn't learn much.

Before knowing about the British accent I used to think that English was the most awful language on earth, then I discovered the bBritish accent and I really got interested into it and I even started learning English in my free time by myself.

Due to that little talk that we had made me, I realizsed that I still love the British accent.

OR
That little talk that we had made me realise that I still love the British accent.

(I have only corrected the spelling of realise because you have stated a preference for the British accent. American spelling - realize, British spelling - realise)

"I always finish what I start" It'is a promise that I didmade to myself and is a mantra that I say to myself when I want to give up.

IfAs I started learning the bBritish accent, I'll keep learning English until my British accent and pronunciation becomes perfect.