Knitting Dilemma

I'm knitting another sweater for myself. I've knit the back and front - and am currently working on the sleeves.

My mother would often knit two sleeves at the same time, to ensure that they were identical. I've been doing this and am at the point of decreasing stitches for the cap of the sleeve.

I've suddenly realized that the sleeves are shorter than I thought they would be.

In the picture, it appears that the model has pushed the sleeves up - but I'm suddenly aware that they are probably three-quarter length! I really don't want them that short!! Now what to do?!

Should I take them apart and try to construct a sleeve that is longer (and tighter at the wrist)? Or should I knit downwards and add on to the wrist?
I think I'll complete the pattern more or less as is... though I may add another inch before beginning to decrease for the sleeve cap... I can always add on to the wrist (knitting in the opposite direction!) if I don't like the way the sweater looks.