If your sibling petitions you, it will be in the F4 category (sibling of US citizen), which currently has a wait for visa numbers of almost 13 years (longer for people born in Mexico and the Philippines).
If you are unmarried, and one of your parents petitions you, it will be in the F2B category (unmarried over-21 child of permanent resident), which currently has a wait of almost 7 years (longer for people born in Mexico and the Philippines). Note that you must remain unmarried during this time (at least not before the parent becomes a citizen), as there is no category for married children of permanent residents.
They can both petition you. Assuming you remain unmarried, and you were not born in Mexico, and the visa number backlogs trends stay the same in the future, a visa number will be available much sooner through the parent's petition.