I recently purchased the 17P navy/black goatskin ballerinas. They're absolutely gorgeous but I needed to size up a full size and a half just for them to be comfortable (normally a 38 in other designers - bought 39.5 in these). I'm terrified they're going to stretch out and be way too large but the toe box of the 39 (my lambskin ballerina size) was way too small for my feet. Is this normal for this material or this season? I love these shoes but probably should return them if they might stretch out.