cider not fermenting

I'm in the process of making my first batch of cider
but...its been nearly 5 days and still no signs of life - no bubbling in the airlock or anything.
I added 11g of dry ale yeast 28hrs ago to see if that would kick it off but still nothing. however I did do a gravity reading today and it has dropped from 1.058 to 1.048, so something must be happening.
Shouldn't it be merrily bubbling away and fermenting by now? or is this fairly normal?
I made sure the juice I bought was preservative free apple juice, and made a starter so I don't understand what the issue is.
any ideas would be much appreciated

cheers!

What temperature did you pitch at? Also try adding a small amount of nutrient dissolved in some warm water.

but the gravity is dropping. is it possible the lid/stopper/airlock is not sealed completely? can you see tiny bubbles evolving from the liquid?
granted 5 days does seem like a long time for that relatively small drop, if you are at 18-22ish degrees

thanks for reply. was pitched twice at 17 degrees celsius. I think I'll wait another 24hrs before adding anything. what kind of nutrient would you recommend? sorry to sound so amateur - my first time brewing anything.
cheers,

ive just taken a 100ml sample for the hydrometer reading and placed it near a heater in the living room and it seems to have taken off, lots of tiny bubbles. so maybe the room it was in wasnt warm enough at 17degrees c. I might heat the room up a few degrees and test my luck.
cheers