Re: Timing when introducing solids
Welcome to the forum!
The rule with solids is that "until one, they're just for fun". That means that until the first birthday, a baby can be well-nourished by breastmilk (or formula) alone, and solids are just for experimenting with new tastes, textures, and motor skills. The baby doesn't actually need to eat any solids as long as he gets the chance to touch, taste, lick, squish, drop, spit, and otherwise manipulate them. That's what baby-led solids is all about; giving your baby the chance to figure solids out at his own speed.
After the first birthday, many babies continue to be primarily breastfed until close to the middle of the first year; it's not like a baby goes from needing only breastmilk on day 364 of life to needing 3 square meals per day on day 365.
It's totally normal for growth to slow in the middle of the first year. Breastfed babies tend to grow fastest in early infancy, and then slow down as they reach the middle of the first year, often dropping percentiles. The reason this happens is that as babies get more mobile, they start putting more of their calories into motion (reaching, rolling, kicking, crawling, sitting up, etc.) and packing fewer on as fat.
So the short answer to your question is: no. There's no deadline. And it sounds like you're doing just fine!!!! Relax, and let your baby get into solids at his own speed. That's what baby-led solids is all about. That, and taking the pressure off of mom. It's not your responsibility to make your child eat solids. He'll get there on his own.
If the upper lip tie is bad, I encourage you to get it taken care of sooner rather than later. No matter how much you don't want to have it snipped now, it's not going to get easier. My 7.5 year old has a lip tie which made nursing very difficult for us, but which didn't get diagnosed until her permanent teeth came in, with a gap between them. Imagine trying to explain to an anxious 7 year-old that the dentist might come are her lip with a laser...
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"