Es muy tu vida

The expression es tu vida, it's your life, can be modified by inserting muy before the noun phrase.

• Es muy tu vida. It's your life. You can do whatever you want. It's no skin off my back.

As you can see, the use of muy doesn't really change the phrase's translation into English. It just expresses more clearly the exasperation or determination of the speaker.

This muy + noun phrase construction is common in related expressions where the idea of independence is involved.

• Es muy tu pedo. That's your problem, not mine. Bronca, rollo or other words that mean problem also work here.
• Es muy tu dinero. It's your money. You can spend it however you want. Don't ask me.
• Es muy mi cuerpo. It's my body. I can do what I want with it. It's not anyone else's decision.
• Es muy mi carro. It's my car. I can refuse to keep it clean if I choose.

This curious use of muy is worth keeping in mind, since as you can see from the glosses above, the word very doesn't appear in the English version. All of above expressions can work without muy, but its inclusion lends a touch of emphasis or aggression.