Ska or Kommer att

[Rosie23xx]

Hej
I recently did the section on the Swedish tree about the future tense or whatever its called and I'm very confused as to when i should use 'ska' or 'kommer att'. So if I haven't made it clear:
Jag ska äta glass
or
Jag kommer att äta glass

I would really appreciate any advice.
Tack!

[MarcinM85]

I'm not a native speaker but I think it should be Jag ska äta glass. Jag kommer att would imply that it is something that does not depend on you. Ska implies that it is your decision to eat ice cream.