My oldest son went straight from nothing to walking at about 10 months. He would get very frustrated with trying to crawl and in the end skipped it out completely! My youngest son was crawling at 5 months. It really is so varied and there is no right or wrong answer. My health visitor said that because my son was advanced with mobility his speech had taken a back seat. But as a whole he was developing well. As long as you are happy I wouldn't worry but any concerns talk to your health visitor. As for weaning, really 4 months is a good age to start. Unfortunately once they are learning to eat you opening up a whole new door of worries. Choking is a every real and scary possibility so try not to force it too soon. You generally get a good feel for when they are ready to start. When they show signs of hunger more frequently and waking up for feeds sooner after settling in to a routine. Again chat to your doctors or health visitor and they will be able to give advice.
They're all very different when it comes to major milestones. My daughter started crawling & pulling herself up at 7 months but didn't walk till she was nearly 14 months. She'll do it when she's ready.
Although 1 milestone that isn't that changeable is weaning. It's recommended to wait till 6 months (26 weeks) to start offering solid food, with 17 weeks being the absolute minimum but only really with medical advice. It's been the same advice for over a decade now. 1 of the reasons is that some babies may be ready before 6 months but unless you can see inside to see if their is completely closed so I wouldn't take any chances & would wait till your daughter is 6 months before starting to offer any solids.
Here's a link that you might find useful:
'The official guidelines are actually pretty clear: you should wait to introduce solid foods until your baby is six months (26 weeks) old - whether he is breastfed or formula-fed (or both).'
But if you choose to wean before that I would seek medical support
It goes on to say:
'Why six months?
Until 2003, parents were advised to wean between four and six months. This was changed to six months after worldwide research (endorsed by numerous health bodies, including the World Health Organisation and the Department of Health) showed, if you wean before six months:
Another - very attractive - reason for waiting till six months is that the whole darn process is a heck of a lot quicker and easier. At this age, your baby is very likely to be able to sit in a highchair, take food easily from a spoon and/or pick up and hold food to feed herself.
Because of this - and because you can offer him a wide range of foods straight away - you can move very quickly onto a good, varied diet. If you start earlier than six months, you will go have to go much more slowly and carefully and the type of foods you can offer your baby will be quite restricted.'
I would say that's pretty clear.
Good luck whatever you choose to do.