I’d start now but if the packs say from 7 months, I’d put them in the cupboard for a bit. There are lots of things you can give until then. Brocolli is brilliant as it has its own handle 
As well as fruit and veg, try things like cheese on toast cut into soldiers, pasta, omelette cut into strips, strips of chicken, cubes of cheese. There lots of things that you can put on toast, mashed avocado, sardines, smooth nut butter and lots of sandwiches too.
Cream cheese on Scottish oatcakes is a good one too. Basically anything can be a finger food, you don’t need to buy special stuff. Just cut grapes and cherry tomatoes in quarters and sausages lengthways to cut down the risk of choking.
If you are wanting to give cereal, these porridge fingers are easy to make and Cheerios make a good finger food when she’s a bit older and got her pincher grip 
Things can get messy though so you might need to buy a couple of long sleeved bibs and put a cheap shower curtain on the floor. One of DDs first means was Spag Bol which she ate a bit of but lots went in her hair and on her face 