Couple of decent runs there and nice tacks, I would get yourself a bit of 2mm or 3mm, allows you to learn the 'feel' easier, torch distance/angle/speed etc without worrying about burning through.
A good start.
I can remember my first attempts at Mig welding. The frustration and then Ha Ha!! something happens.
It is a great sense of achievment.
The next thing is to work on consistency, but it looks as though you are on the way.
A good intro to your thread as well.
Your next mission is to chop up your old push bike and build a chopper.