Isn't she currently serving?
Can't she pursue this now?
The Congress is not under the control of Harris's party, but rather is half-controlled by Trump's. That means her party and Biden could not pass anything, especially something that made her look better to voters.
Is this the first policy point we've seen from her?
No. Unlike the Republicans, who are very thin on policy and make the election mostly about Trump's personality, Harris has a very detailed policy agenda which she talks about constantly. The biggest and most popular of these is
keeping abortion legal in the US.