YES, it will be extremely touchy in terms of pitch, and you will fall right away, many times
Roll is stable as a rock, and you can not really influence the board much or at all, by putting weight on the rails, so dont do that.
The roll balance will be kept by itself, really amazing, so dont worry about it at all.
You will not be able to foil at a low height for starters, eventhough this sounds "tempting and easy".
When you get up, you will have to learn to manage the pitch/height, and this is the difficult part that for most riders takes a lot of time.
And you WILL fall, when you get up, and most likely will the foil shoot out of the water, while you plunge into the water to windward or leeward or forward - thats normal and you have to try again and again.
Use a helmet, and close your eyes and take your arms up in front of your head, so you dont get hit "wrong" by the foil - as you will most likely not have much orientation the first times.
Later you will learn to fall and know how to fall and how to avoid trouble with both the board and foil
Enjoy and have fun - it is AMAZING, especially the first short times you get up !
Dont worry about acceleration and high speed - as you wont be able to ride so long that this will be an issue
Like said before - just go out and do it.