I wonder if she wants to win a referendum anyway...
If she wins then she has to negotiate a way out of the UK and that will be infinitely harder than getting the UK out of the EU because Scotland is much more integrated into the whole economic, industrial and political fabric of the UK. She then has to start governing Scotland but call an early General Election - which could weaken her government straight away since her party's primary aim of independence would have been achieved. The EU wouldn't welcome her with open arms whatever she may think. I don't think she could look forward to an easy ride and she would soon become responsible for anything going wrong - you can only blame the previous government for so long (and, for many things, the previous government would have actually been, ooh err, the SNP....)
If she loses, however, especially by a narrow margin, then she can keep blaming the nasty English for Scotland's woes, keep subsidizing Scotland from the Barnett formula, demand more concessions & money from London whilst perpetually threatening another 'once in a generation' referendum and keep in Government thanks to a combination of harvesting the anti-English protest vote and promising things that she "would deliver if only Westminster would allow her" whilst knowing that she couldn't because Scotland's economy alone wouldn't support it.
For Nicola Sturgeon, losing the referendum would be a win-win situation...