Hi,
My DS didn't nap in his cot until he was well over a year old. I used to rock him to sleep, then put him on the sofa, bed (obviously wedged in with cushions and never unattended) or I put him on the doo moo.
When he got too big for me to rock to sleep I put him up in his cot for naps, he screamed for the first couple of times, but 'got it' quite quickly.
That was our home routine, he went to nursery at 6 months old and they had him napping in a cot with other children in the room within the first week!!
Will she not sleep at all if you put her in the cot? Have you tried leaving her for a little while to see if she'll settle herself? Does she go down ok at nighttime?
Look, don't worry about it, I find the best thing to do is to go with the flow on these sorts of issues. Kids are pretty smart and tend to work things out for themselves.
And don't worry about nursery - they'll have her sorted in no time, it amazes me how quickly children get into the nursery routine. My nursery has them all fast asleep in the bunks in the sleep room straight after lunch, you wonder how a room of 8 toddlers can possibly be a good place to sleep! But it works.
You'll be fine, try not to worry.
xx