Hi Jammi - my DS is 10 days younger than yours and we have just started weaning at 22 weeks/5 months although I was planning to wait until closer to 6 months.
I tried to ignore the putting things in his mouth on the basis that he does that with his toys, his books, the remote control, his socks etc. Similarly, he watches everything we do so I didn't let that sway me into giving him food. In the end I decided to start after 4 weeks or so of increased demand for milk feeds and fussiness after feeds as if he is not getting enough, plus often 'snacks' in between big feeds. It seemed more than a growth spurt as it was continuing and getting more demanding. He also started sitting unaided last week and is very dextrous at picking things up and getting stuff into his mouth etc. so that was the green light for me.
Anyway, I've pureed some veg and am offering it to him during one feed (was a bit scared to try with chunks of food!). However I am trying to take a BLW approach to purees. So I do let him lead - he plays with the food on my and his fingers, he uses the spoon himself, he tries to drink the puree from the little bowl (he is obsessed with us drinking, more than eating even, so is trying to copy us), and when he is done I stop. Two days ago he ate a whole ice cube of pear and several raw blackberries that he had helped me pick but he only ate a little bit of carrot yesterday.
As he is under 6 months, I don't want to force him into more food than he wants and will let him set the pace, but it was clear to me that he was ready to start trying. I still make sure he gets a full milk feed when giving him the solids - one breast before, offer food, then on breast after. He still feeds very well on the second breast so unsurprisingly it is clear that the solids are just a bit of fun at the moment rather than satisfying his appetite at all.
This weekend I might be brave enough to try BLW and try steaming some broccoli florets or carrot batons and seeing what he does with it!!!