ICE ERO and going to specialized units

I am 40 years old and thinking of joining ICE ERO. Curious how long does it take now to get into a specialized unit or how hard it is? An example of a specialized unit would be the special response team or anything else that gets lots of action?

I wanna be able to do something fun with lots of action. I am also open to hopefully getting my foot in the door and be transferred into anything in the federal arena.