XPX Garment 5 Pack Stripe Lovely Cat Little Girls Boyshorts Knicker Baby Girl Cotton Boxer Briefs Hipster Underwear 4-10 Years

My daughters only 4. But she’s in 6-7 year clothes. Her 6-7 bikini type underwear are quite small (primark). What size would you say to get in these?

Do these have a high waist?

What age size equivalent is a size xl? there is no age reference on the label and i’m unable to confirm what size i’ve been sent.