Originally Posted by RooseveltL

If United sold you the ticket with minimum connection time - you should be okay. I can't tell from your airport code if EWR is first stop in the US (unless a typo) as UAL doesn't recognize the code. Typically arriving via international requires clearing customs which can be quick or awful long. You will also have to pick up your bags to recheck for onwards travel.
In your favor - it is likely your inbound travel is early (pending head/tail winds).