Ant-Man comes after Avengers so that's not possible unless they only explore Ultron's origins in Ant-Man
I knew both were 2015, but was unaware of exact release dates.
"With that in mind, I humbly add my own prophecy of what the dawn of the new millennium shall bring forth: one thousand more years of the same...old...crap."
"Once again, science saves the day. The end."
-Hubert J. Farnsworth