Til about 12 months, breastmilk (or formula) should be the primary source of nutrition and therefore, it is best to offer first so that solids do not displace milk intake. DD was around 10 months when I stopped worrying about when each was given in relation to eachother (in other words, not specifically offering solids first but not going out to my way to offer breastmilk before solids either) and just kept an eye on how many breastfeeds she was having in a 24hr period.