Well, as I think I've said before, Wallace is a Scottish name, but it actually means 'Welsh'.

(Not literally from Wales, but the inhabitants of south west Scotland were British Celtic, and spoke Welsh well into the middle ages)

So she's certainly Celtic, anyway.

ETA: Nice to see we're chillin' out again.

True.
The gaelic Scots originally came from Ireland, and gave their name to the whole country.

But the origins of the people of Scotland are a mixture of Scottish (Gaelic), Pictish, British, Anglian (English), Norman and Norse.
DNA can distinguish between celtic, germanic and norse influences in a persons ancestry, but can't narrow in any closer (as yet).