I-20 will be issued to you only if you are accepted and you or your uncle can provide financial documents to cover your tuition and living expense. With the admission letter, I-20 and financial document you can apply for an F1 visa. If your uncle is not a US citizen or permanent resident, I don't think he can sponsor you to study in US.
Since you uncle can't sponsor your immigration to US (Only parents, spouse, childern, brothers or sisters can sponsor), I don't feel you will be considered to have immigration intention.