Hi vics,
I'm not sure what kind of Jasmine you have. If it's the common white flowered one, (J. officinale) It would usually be pruned, (if at all) after flowering which is in the summer.
The best position for it is a warm and sunny site for it to flower well.
If it's the winter Jasmine, (J. nudiflorum) with the bright yellow flowers, it should be pruned in march, just prune back the side shoots that have flowered and thin out some of the old wood to keep it tidy. Good Luck. Tbird+