Let's look at their differences:
Pronunciation
. If you haven't paid attention to it yet, you can listen to British radio ( BBC radio ) and American ( Voice of America ) one after the other - the difference in pronunciation is obvious.
Vocabulary
. The British and Americans use different words for some things. Offhand, there are about 500 of them. For example, “shop” in British is 'shop', and in American is 'store'. And in most cases, the British and Americans not only do not use the words of their “colleagues in language”, but sometimes do not even know them at all.
Some
words are spelled differently. For example, the word "color": the British spelling is 'colour', the American spelling is 'color'.
Grammar
. There is a slight difference in grammar. For example, in American English, the 'Present Perfect' tense is officially used in fewer situations.
Richness of expressions
. British English is richer in terms of words and expressions. The American one, being a derivative of the British one, did not borrow everything from it - a lot of words, phrases, etc. remained, so to speak, "overboard". In other words, the baggage of British English has been accumulated for centuries, and the Americans have taken only part of it. Therefore, it is generally accepted that American English is “easier”.
With all this in mind, here's a tip:
First
, choose one of the English options. Follow it 100 percent - pronunciation, words, expressions and grammatical features; use learning materials based on the option you choose; listen to radio, audiobooks, podcasts, etc. and read material and sources in your choice of English, at least in the initial stages. Why?
First, to lay the right foundation for the language. If you take information from "mixed" sources (ie both British and American), "your English" will turn into an incomprehensible hybrid. Native speakers themselves do not do this - the British speak British, and the Americans speak American. Why should you do this?
Secondly, it will make it easier for you to master the language, especially during the period of getting used to the language - sound, vocabulary, grammar. If you interfere with options, "porridge" cannot be avoided. If you listen to something with a British accent, your subconscious gets used to it. And if tomorrow you already listen to something in American, there will be a “failure” in your head - what you heard yesterday does not correspond to what you hear today - then what to remember, what to get used to?
At the same time, one should not take the choice of option too seriously or critically. You just need to start with anyone. Despite the differences, it will still be authentic English, with which you will not be lost.
In the future,
you can add a second option. When your knowledge has already “strengthened” and a reliable base has been created, you can expand the circle of sources. It's even useful, as it helps you understand the key differences between the two options and navigate different situations.
For example, if you've learned British and you're talking to an American, you may hear the word 'flat' (apartment) familiar to you, but you'll understand that he means "a flat tire" - that's how the Americans use it.
At a more advanced level, you can "retrain" to use a different variant of English. You can even master both and, in the right situations, “switch” from one to the other. All this is real. The main thing is to start, take the first step!