There can be errors with gender selection so I wouldn't count on it 100 percent but they do seem to have a decent success rate these days.
Hi. I believe not all the countries allow gender selection. My clinic, for ex., uses it only to exclude the possibility of transmitting the genetical disease to a future baby. And if we just wanted to select the gender just because we wanted to have a boy..Then we'd definitely fail with this intention. Anyway, it's your personal decision unless the possibility is not regulated on the country level. Good luck!