You can legally have sex at 17. This is called the age of consent, and is the same whether you are a guy or a girl, and whether you are straight or gay.
There is no age restriction on the purchase of condoms, so you can buy condoms at any age.
Abortion is illegal in Ireland today, however the right to information and the right to travel is not. This means that you have the right to seek information concerning abortion, if your doctor will not give it to you they must point you in the direction of someone who will. However, it is important to remember that if you are experiencing a crisis pregnancy you have 3 options, abortion, parenting and adoption.