I agree with the others that the angle is too high. The center of a TV should be in the middle of your seated head level view. Depending on the technology of your display if you get too far from that center view the quality of the image degrades. You also need to aware of operating temperature range of the TV which will be far exceeded when the fireplace is in operation.

You definitely DONT want the tv in a dining space, Post an accurately drawn floor plan of the entire 12 x 26 space, with all windows, stair , walls, openings in INCHES.

If you're not willing to move the furniture in order to access the only other plain wall in the room, then what else can you do? we don't have a magical answer for this. putting it in the corner looks weird. So, that leaves the fireplace. Remove that large mantle you have and do something different. I'd also do something w/that brick. that fireplace could really become a focal point. I don't think you're seeing the potential of that room of yours. some other ideas what's wrong w/either of these? I think they look great. BTW, if you did closed cabs beneath the windows like they've done here, you'd have all that storage for toys and stuff! (ditto if you did hinged benches under the windows. you could hide all of the toys) they don't even have to be built in. just make them to fit under the window and top w/pillos. I love this idea if you have the two windows. this is about the size of your fireplace. a larger tv will work fine. another one w/o windows, but gives you an idea what's to the right of the fp? another window? if not, you could try this: If there is a window to the right and you really don't want the tv above the fp, then consider removing the window OR, put in a smaller window and raise it up towards the ceiling. then you could do something like this (the window would be more of a transom style where this light would be) this is what I mean by changing the furniture. imagine the tv is on the wall across from the fireplace (and those chairs aren't there)

I like next to the fireplace. Find a drapery for the window in the same color as the wall. Put the chair in the toy corner to balance and also open up the entry to the room. Maybe the toys could go in a furniture piece under the tv.