I have a question :
Is this sentence true?
わたしはかのじよのいもうよありません。for (I am not her younger sister)
In 「わたしはの名前ソフィアです」 you're mixing two particles, the 「は」 particle and the 「の」 particle.
The 「は」 particle marks the theme of the sentence. Many western languages are "subject-prominent". That basically means that the subject is very important in the grammatical structure and can only rarely be ommitted.
Japanese (and other east-asian languages), on the other hand, is "topic-prominent". That means the topic of a sentence is very important. The subject is less important. In fact, the subject is regularily ommitted.
For example, "I am well" would in most cases just be 「げんきです」 (or 「元気です」 written with kanji). The same sentence could mean "You are well", "He is well" and so on, because there's no subject in it. The listener would be expected to know the topic from the context. If somebody asks you whether you are well, you'd probably not answer "He is well", but "I am well" ;)
But what if the topic isn't obvious from the context or you want to change the topic? Then you can use the topic particle 「は」.
So, 「わたしはげんきです」 (or 「私は元気です」) means expressively "I am well".
Be careful not to mix up the topic with the subject. Those two are not necessarily the same. For example, if somebody asks you about your favorite food, you might answer 「わたしはパスタです」 or 「私はパスタです」. This means something like "As for me, it's pasta". It doesn't mean "I am pasta" ;)
So, to come back to your example sentence, you could say 「わたしはソフィアです」 or 「私はソフィアです」 - "I am Sofia" or, to make the topic stand out stronger, "As for me, I'm Sofia". But in most cases it would be completely fine to just say 「ソフィアです」.
Now about the second particle, 「の」. This particle is used (among other things) to combine nouns. That mostly expresses a relationship from owner to possession, from large to small, from general to more specific etc. For example, 「ソフィアの犬」 would be "Sofia's dog", or 「日本の車」 would be "Japanese car".
In your example sentence, you probably wanted to say "My name is Sofia". "My name" would be 「私の名前」, so the sentence would be 「私の名前はソフィアです」. Please note that you need the topic marker for the combination 「私の名前」, if you want to be that verbose. As I said above, just 「ソフィアです」 is completely fine.
Similar to above, the 「の」 particle can replace one of the nouns completely. So if you're asked, which car is yours, you could answer 「赤いの車はです」 ("It's the red car") or just 「赤いのはです」. It's just understood that you're talking about your car and not about anything else.
Your second sentence is a bit mixed up as well, I'm afraid. But this comment is long enough as it is, so I'll leave that for another time ;)