I see this is an old post, but for anyone else reading it, I have some opinions to share. Everything in life is mindset. If you expect Spanish to be a barrier, it will be. However, I was born and raised here and though I am not proud to say it, I still don't know it hardly at all (I can't converse in it!) because I almost never have to speak it. You will be fine. I actually want to learn it better. It's the perfect opportunity, where else can you go and try to converse in a different language and go back to your native language when you get in over your head. LOL
Regarding safety. I just moved from back from a long stint in Indiana and there were parts of Indianapolis (where I spent many years) that I felt more threatened than any places I have visited here in El Paso.
In summary, I am certain that you will find El Paso quite welcoming. There are many people from many places due to the base. There is a lot of wonderful food and culture here. It's not like any other place.