I don't know what poll you saw but according to a Reuters poll today, she has the lead with 47%-42%.
Of course she did well. I've never seen a candidate do better at one of these, and Trump did...what he always does, lies and rambles on about nonsense. "They're eating your dogs and cats." She put the bait out there and he fell for it every time. It was like Road Runner drawing a tunnel on the side of a mountain and then changing the sign. Trump ran straight for it every time. Not that it matters to those who are either in the cult (37%) or to those who all they know is they were doing better financially under Trump, or those who just hate Democrat Marxist trans woke feminist critical race theorists, etc. I don't like some of those too. But my disagreements with her or her shortcomings will be much less damaging to the country than Trump's consistent contempt for constitutional norms. He's the greater threat to America than the progressive mush that Harris might bring.
Then Taylor
publicly supporting her means at least 10 million+ typically non-voting young people will probably be voting (Harris) who otherwise might not have.