Unlike hormonal forms of contraception, there is no legal age limit to buying condoms in Ireland. However, shops do have the right to refuse to sell you anything, so if a very young person was to buy condoms, understandably this might set off some alarm bells.
Condoms are usually kept behind the till in small stores, but are up at the front, beside where you pay, in many pharmacies. There is no need to feel embarrassed or ashamed of buying condoms, if anything you should be very proud of yourself for looking after your sexual health. Well done you!