It's very good that you practice a lot beforehand. This does help in lowering the anxiety levels to an extent. I would recommend that you use such words in your presentation which you can speak more comfortably, I did that myself during my online presentation. Remember to never lose faith in yourself, no matter what, in the end things will be alright. You can do this. Stay calm and don't just read the script out like a robot, add your enthusiasm and quirkiness to it. In the end, I'll quote Benjamin Mee from We Bought a Zoo, "You know, sometimes all you need is twenty seconds of insane courage. Just literally twenty seconds of just embarrassing bravery. And I promise you, something great will come of it." :)