General Purpose Antonym for "Ago"
Solution 1:
"From now" makes sense for the purpose you're suggesting, but if you're after a single word I think "hence" carries the same meaning.
Solution 2:
If you are setting the labels for a time machine, both clarity and brevity would be nice. "Ago" is the clearest shortest label for anything in the past, and "ahead" is my preference over "from now".
Side note: Ago comes from the Old English agone, meaning "departed, passed away", as in gone.