I suppose you could say we have sort of started as my LO has tasted some food (including carrot and asparagus), although at the moment all I am doing is putting a veg on the table near her at dinnertime. She picks it up and eats it.
She started picking food up a while ago, has been picking up toys and 'eating' them for ages... when I found carrot in her nappy after a family meal, I decided to let her have the dinnertime veg available if she wanted to pick it up.
My LO was 15 days overdue and so I am going to cheat and start early I think, although I'm not going to 'feed' her anything, just put safe food on the table and not prevent her from having it I think. She has been able to sit upright, unaided, for lengthy periods of time for about two weeks I think. Her weight gain had slowed right down, and she now wakes 3 times a night after sleeping through for months. She breastfeeds very very frequently during the day (always has done). I know these things don't necessarily mean she is ready for food so am being cautious - but I also think if she is able to feed herself then it probably won't hurt for her to have a veg. Also - and this is probably a selfish thing - she sits for ages now at the table with us, where before one of us had to hold her while we ate (she always hated the bouncy chair or high chair without food, and would cry unless held and sang to etc throughout the meal).
At the moment she only has that veg. I think when she is 5 months (so 5 and a half in the cheating way) I might widen the range of foods slowly until she is 6 months and can have pretty much everything.
There are some others on here who started blw before 6 months who might be able to give more advice.
Regarding the toast and pasta - I think gluten (wheat) is off limits until 6 months old - but I am not 100% sure. I am not going to give it until 6 months anyway, to be on the safe side