Do wildflowers come up looking like weeds?
Wldflowers are often sold in seed mixes, so it's hard to predict what the plants will look like. Yes, this can make the plants look like a patch of weeds at first.
If the seed packet includes a list of the types of flowers included, you can look up each plant individually to see what its leaves look like when it is a seedling or an older plant. If not, the only way to tell is to wait for them to flower.