こにちは おげきですか わたし わ デイエゴ
Hello how are you I am Diego
Welcome to Duolingo, Diego!
If you don't mind my advice, I have a few minor corrections.
わたしわデイエゴ。 This sentence is missing an important part - the verb.
It should read わたしはデイエゴです。 The word "です" is equivalent to the English verb "To be". Without a verb, this sentence would literally translate as something like, "As for me, Diego." It needs the verb to tell the listener how Diego relates to you.
The particle wa is not the verb, but rather it acts as "topic marker", letting the listener know that わたし (Myself/I) is the subject of the sentence. It's worth mentioning that you could introduce yourself using the shorter sentence "デイエゴです" which omits both "watashi" and "wa". This sentence doesn't have a subject, but it can be assumed based on context that you are speaking about yourself. It is quite common for native speakers to drop the subject (or other parts of a sentence) if it can be inferred from context or has already been established earlier in the conversation.
Also notice that the topic marking particle is pronounced "wa" but it is written with the hiragana character は (HA), not わ (WA), like you might expect. Isn't Japanese fun? :-)
Lastly, although it is not rude, the phrase おげんきですか？probably does not belong in a Japanese introduction. Asking someone how they are doing is a polite set-phrase in English, but the Japanese language has its own standard greetings and phrases that are more appropriate when meeting someone for the first time.
I would recommend using the following format for first time introductions:
わたしはデイエゴです。Watashi wa Diego desu.
(or just デイエゴです。) (Diego desu.)
よろしくおねがいします。 Yorushiku onegaishimasu.
はじめまして。Roughly translates to "Nice to meet you (for the first time)", but more literally means just "A beginning" or "It starts."
わたしはデイエゴです。 "I am Diego"
よろしくおねがいします。Roughly translates to "Please treat me well." or "Please be kind to me" , but is often times translated as "Nice to meet you" in English, since we do not have a good equivalent.
I hope you enjoy learning Japanese. It is a fascinating language.