In Premiere Elements, you don't convert. You Publish & Share.
Although you can Publish & Share your video project to a Windows Media file, WMVs are all but obsolete.
I'd recommend you use Publish & Share/Computer/AVCHD with the YouTube HD preset. This will give you a high-quality video that should play perfectly on any Windows or Mac computer. (Although I also recommend you download the free VLC Media Player rather than use the built-in Windows Media Player. It's a much better, smoother media player and can play almost any type of video file.)
Important: what computer operating system is involved?
Depending on all factors....
If file size is a major requirement for your export, then I would indeed consider the Windows Media Video 9.wmv file from Premiere Elements 13/13.1/
What are the properties of the Timeline content that is heading for export?
Example: If you have a 1080p file and 1080p project (1920 x 1080 @ 29.97 progressive frames per second), then look at the following export settings for the
with Presets = WMV - 720 x 480 16x9 29.97.....then under the Advanced Button/Video Tab of the preset customize the export settings to 1080p. Please refer to screenshot
Note: I have the Bitrate to 10,000 Kbps (kilobits per second). That 10,000 Kbps can lowered to where you get a smaller small sized wmv video and still maintain quality.
Please consider your choices, and then decide what works for you.