It is a nice little baby, but expect more like 36-38 inches, 31 inches as a 5 month old is a TALL baby. My 36 mare was 26 inches at 8 months old. If that gives you a starting point for height. She does look silver bay, but miniature tend to shed out lighter than what they are as babies, her mane will most likely grow in lighter also. So expect more towards the sorrel with lighter legs and flaxen manes and tails. Is she duel registered with AMHR and AMHA or another registry. AMHA will not accept anything over 34 inches tall even if the parents were registered with them. The AMHR will accept up to 38inches in their B division. In the AMHR there is the A division which is up to 34 inches and the B division, over 34 but not to exceed 38 inches. She is definitely the arabian style miniature though, no doubt about that face.
You know how to make a miniature horse even smaller? Leave them in the dryer a little longer!
"Don't ever regret something that once made you smile"