Playpen/barrier

I have a lovely large rectangular Skip Hop play mat for my baby, and she is now at the crawling stage. I feel terrible always stopping her from going beyond the mat, and also always stand close because she could bump her head on the skirting or wall when playing. What barrier/gate type thing could I use around the mat so make it safe for her?

If there isnt anything suitable, are there any nice large-ish play pens? My mat is 218cm x 132cm. Do not want smaller or larger than this. It’s a good size for her to roam around I think