Julia, Unbridled Soul

When Julia, Unbridled Soul enters the battlefield, you may sacrifice an artifact. If you do, draw a card.
At the beginning of your upkeep, if you control a creature named Winston, Secretive Rebel, put a +1/+1 counter on Julia, then up to X target creatures you control gain hexproof until the start of your next turn, where X is the number of +1/+1 counters on her.