It's not slipping any that I can notice.
FYI, the timing belt is cogged - it won't slip. (A cogged belt could potentially "jump", but if it did the car would probably not run - or run really, really badly.)

When a cogged belt is toast, it generally snaps. Then some nasty, expensive stuff happens inside an interference engine.

Some people are comfortable inspecting their belts for visual signs of weakness (cracked/hazed rubber) to decide whether to change it or not. Personally, I wouldn't risk it, knowing the history of belts on this engine.