This looks like a juvenile betta or a small female. Maybe someone more experienced can chime in, but I would wait a couple of months to see if it matures to make gender and tail type more clear. A better, less blurry, picture would also help. When upgrading the tank, make sure that it is at least 2.5 gallons with a filter and heater. Read up about the nitrogen cycle, it will prevent issues in the future. Use silk plants and other soft decorations. I would love to see more pictures and the new tank (when you get it)!
If it is a female, it is most likely a veiltail female, but it also looks like a juvenile betta.
If your betta is a mature female, it will have an egg spot- a tiny white dot between the ventral fins at the bottom of the body.
When a betta is young, it is actually difficult to sex it. Some males even have a fake egg spot when it is young.
The picture you provided is kind of blurry so I can't see a lot of detail.
And yes, make sure the upgraded tank is at least 2.5 gallons, is cycled (Nitrogen Cycle), has a filter and heater