Sourdough Stater underway - time to bake?

The latest news is that we seem to have a reasonably active starter bubling away here. I say, "reasonably active" - I have no real idea what it is supposed to look like but as the pictures below show, there is no more 'hooch' and about half an inch of bubbles on the top
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Day 7 - just halved & fed

Day 7- Lunchtime - bubbling!

Day 8 - Lunchtime after feed

Yesterday morning I halved the mixture and fed it with 100gms strong white flour and 100ml tap water.  By lunchtime there was a foamy top and it had visibly risen.  By this morning it had shrunk back a bit but was still bubbling so I halved it again and did the same feeding routine.  By lunchtime about 3 hours it was back up to about the same level.  The smell is quite fruity with a vinagary backnote which catches the back of the nose.  Reminds me a bit of the smell of vinyl matt emulsion.  So the question now (and one our 10 year old daughter is asking too!) - Is it ready to use fore baking a loaf?   Well... I suppose there is only one way to find out!