OOC: Yeah, I get it, I do think tampering with age can be odd and there would be awkwardness.
But I think, in a way, it could fix things too.
For Evan, it's really great to have Christine back, and he loves his sister for who she is. But you have ti admit, in his mind, there is probably a disconnect in his mind. His memories of her are all as a child, it has to be confusing for him because his "final" memories of her are her at the age of 15, but what's in front of him is her at the age of 27 or 28, and nothing in between. That's gotta give him vertigo. One half of him wants to be in over-protective brother mode and the other half has to be reasonable and remind him that she's an adult now.
For Christine, I imagine the vertigo is worse. That's a huge jump between 15 and 27-28, mentally and physically. I don't even know how her mind has held up, that's a lot of mental development there that she just kind of skipped over. And there just has to be like a blank, empty period in her mind where the portion of her life that she should have gone through would have been. She can do adult things now but her maturity level just might not be there. She doesn't know whether to act like a teenager or an adult some of the time I imagine.
I'm not trying to convince you or anything, just rationalizing the thought.