With the sail all the way to the front, it'll probably be difficult to lift off. If you find you need a lot of pressure on the back of the board to ease of the water, bring the mast base back.
Don't lean back or out, try to stay over the board. If you lean back at the same time you are pressing hard on the back foot to get off the water, once it's out, it'll shoot to the moon.
Aim for 15ish for wind. Try to skip like a stone at first. Don't worry about trying to stay high and it's okay if your take off has a couple of bounces on the way. If you aren't going fast and it seems to stall, put it back on the water. Continuing to point to the sky when you are going slow won't solve anything.
Yes, too much wind is no fun at your stage, especially with a big wing. Since you have something floaty, rig down if the wing picks up so you aren't fighting things. 25 is fair amount of wind for a beginner. At your stage, rig for the gusts not the lulls.
That quiet the first few times is a blast, isn't it?

(After more than 3 years, it still is for me)