Firstly, well done at thinking about investments at 18 - I wish I had that attitude at that age !!
The Irish market is different in 2 major respects in my view - banking arrangements and tenancy rights. These make the kind of strategies you see in other markets difficult to replicate here.
Irish banks insist on high LTV ratios for non-buy to own mortgages. They also charge high interest rates. Finally, most of them don't really do interest only mortgages, and insist on capital repayments. Take BRRRR (Buy, renovate, rent, re-finance, repeat - I hope I got that right). When you need 40% deposit plus cost of acquisition, and you have to make capital repayments on a mortgage with rates over 5%, its hard to make that strategy work, as you wont be able to extract enough equity from your first property to refinance and repeat - especially when you are making capital repayments on a mortgage.
Even if you get past the finance issues, the regulatory environment makes becoming a landlord very risky. If you end up with a rogue tenant, the potential costs are massive. There's lots of horror stories on that side in other posts on this forum.
Overall, Ireland is not an attractive location for a budding RE investor.