What difficulties might a 6ft shapeshifter have in impersonating someone 12in shorter?

Question

In one of my settings, I have a character who is given the ability to shapeshift. Her default appearance after obtaining this ability is much the same as it was before. The important part, for the purposes of this question, is that she is a 6'0" human (183cm), but wears heels so that her effective height is closer to 6'2" / 6'3" (188-191cm).

Let's say she shapeshifts into another human female, who is 5'0" (152cm) and does not wear heels, with the intent of impersonating her. Suddenly she has to get used to the fact that her limbs are a few inches shorter, her stride is shorter, her field of vision is significantly lower...

What difficulties might she have in adjusting to a body that is suddenly a foot shorter than what she's used to? Would the average person suddenly become clumsy in this scenario, or would they get the hang of their new body pretty much straight away?

Assumptions:

• She has no secondary power that allows her brain to instantly adjust itself to her new body. Hence me asking how the average human would cope in this situation.
• Teenage years notwithstanding, she has no prior experience of being 5'0".
• I'm not yet sure how to handle the Shapeshifter Baggage issue (warning, TV Tropes link!), so don't worry about how her centre of mass/gravity might change.

Answer 1

Being a 5'0" woman myself, I mostly know the reverse effect from wearing heels and riding on horseback, both of which come with the added difficulty of having a tool or animal to control in addition to your own body. I did sit in a whelchair for a very short time, pretending to be a disabled person for a dog-training class, but didn't need to move then. It's a simple thing you can do yourself (take any chair, no wheels needed) - just sit down in a crowd and give yourself a minute to take in the different view.

That said, there would definitely be a half-minute at the least of taking in the effect of the new perspective. Suddenly being taller allows you to see much more; for me, the two inch of my heels make the difference of being able to look over the top of supermarket shelves. Being that much shorter may make it harder to spot landmarks clearly visible before, you're more likely to just disappear in a crowd. Also, other people are suddenly huge. I am so much shorter than the average person around me that I have to strain my neck talking to them, as I have to constantly look up; being suddenly shorter feels intimidating and uncomfortable.

I'd expect a shapeshifter to adapt to her new body for motion within a few minutes, as the human brain is pretty much made to use tools as extended limbs and can recalculate distance fairly quickly accordingly. The effects above (lower field of vision, being constantly looked down to, having to run faster and further for the same speed and distance) are psychological effects she will experience either conciously (for storytelling) or unconciously (she'll feel exhausted a lot faster, have an uncanny feeling of everything being just a bit of, be irritated for 'no reason' and get angry if people talk down to her both literally and figuratively).

A point I'd also like to mention is that people react differently to you if you are the size of a child. Might be just me, I look pretty young as well, but a lot of people guess your age according to your height as well. People are less likely to take you serious and will be more condescensing. However, given that your character likely shapeshifts to impersonate someone else rather than just shrinking, people treating her like that other person is to be expected anyways. She just might come to understand a few aspects of her character a bit better after having walked a few miles in her shoes.