Reducir tamaño Video Error

Good Morning,

I have a video that I need to edit (just crop) that has an initial size of 137MB.

When I upload it to premiere and edit it, and open the window to export it, it comes out as an estimated 7000MB size, I modify the parameters of the video to reduce it:

Form: H264.

Default setting: youtube1080 (I've also tried 720)

In addition, I lower the speed to the maximum to reduce the size as much as possible, however although it lowers, it continues to make a lot of weight in the estimated size: 2000MB.

When I export it, that size does not appear, in the properties of the file it tells me that it weighs 658MB.

I'm new to this and don't understand a thing ...

If the video weighs as little as it starts, then it may go up so much? What do I do to make it weigh less than 500MB (which is what I need)?