I would say start around 6 months, when you both feel ready. Ideally, she should be able to sit up relatively unaided (not tipping over to the side or leaning back in the high chair) to prevent choking. This might be a bit later if she was a preemie, just trust your gut on when you feel it's right to start. There really is no hurry and you can start slowly. We did just one meal a day for the first month and went up to three meals by 7.5 months. No you don't reduce her milk feeds, just add in a little bit of food at a meal when you sit down to eat anyway, and keep offering her as much milk as she wants. It will reduce in time on its own, but she won't be eating enough to start to make up for a reduction in milk feeds. We didn't see milk start to reduce until probably about 9-10 months.
We did baby-led weaning and it was amazing. No extra work making too many special things just for her as she mostly ate what we ate, or some variant of it (for example, if what we were having was a spicy curry, initially I made her something different or a milder version of the same. Now that she's older, she eats everything we eat, even spicy foods). I really do believe it's why we've had limited periods of fussy eating and now have a 3.5 year old who eats a wider variety of foods than most adults do. We literally rarely go out for a meal without a stranger commenting to us about how amazed they are that she's eating what she's eating at her age. Whether you do BLW or purees though, from 6 months, they can have everything except whole nuts (nut butters are fine), honey (unless it's well-cooked in a recipe), or added sugar and salt. If you or your partner have any food allergies though, I'd take it slow introducing those specific foods, otherwise, there are really few things she can't have and you don't have to introduce things slowly or staggered. Our daughter's first meal at 6 months was a Sunday lunch and she had roasted carrot and parsnips with garlic and rosemary, a yorkshire pudding and mashed potatoes. So you don't have to do purees at all, though if you do, obviously it's always better to try to make them yourself (just puree what you're already eating, before you add lots of salt or whatever) because, of course, it's much cheaper, but also means your baby gets used to the types of foods you already eat. That way when you do transition to all eating the same things, it will already be familiar, even if the form will be a bit different.
