Welds look good, you're definitely on the right track, try not to get into the habit of weaving all the time though, it wastes wire and gas, puts a lot of heat into the job but most of all the welds aren't as strong as stringer beads
Agreed, the welds are amazing if that is your first.
You mean first welded project?? You must have practised before making those welds. They are very neat for Mig welding, I agree with the above poster, no need to weave as much on thick box section.