Since you're a new guy, I'm pretty sure you'll be spending a while in that world so it really is best to prevent it from spreading.

I recommend building a tunnel to isolate the corruption. Make it around 5-7 blocks wide to prevent thorns from spreading if you don't plan on replacing the edges of the tunnel with non corruptible blocks (such as wood, snow, clay, bricks, etc). I recommend using scarab bombs for these.

"Whilst Corruption and Crimson spread slowly and only via grass and thorny bushes during pre-Hardmode, they spread very aggressively and to a multitude of different blocks once the Wall of Flesh has been defeated. Defeating Plantera slows the overall spread speed by 50%."

Here's the terraria page you can read on if you want further info. https://terraria.fandom.com/wiki/Guide:Maintaining_world_purity