Can I find out what a State Pension is worth for me assuming starting in 2021, aged 37 with no previous civil service
First off, it is the Public Service pension that you want to estimate. The State Pension is what you will be awarded based on your PRSI record (formerly the "Old Age Pension")
Secondly it is very difficult to say how much your Public Service service will amount to as it is based on career average earnings, with a certain percentage of your salary each year counting towards pension. Even if you can guess that you will start at €80K and finish at age 68 on €110K (all on today's terms) it is still difficult. It depends if you make rapid progression up that scale in your early career (good) or only in your latter years (not so good).
However, here is a very rough estimate based on a starting salary of €80K and finishing at €110K on a promotion/incremental scale which yields a
career average salary of €100K. Your normal retirement age is presumably 68, so you can expect to have 31 years service.
Estimate is (€100K * 31/80) - (13K * 31/40) = €38750 - €10000 =
€28750. (The €13K is the approx current State Pension rate).
In addition to this roughly estimated PS pension you also apply separately for the State Pension based on your total PRSI record. If you have already been paying PRSI in your current role then these contributions combined with your future contributions in your new job should get you a full State Pension.
You can make your own estimate using notional career average earnings using the above formula. Just to emphasise though that this is not an official formula and is only a rough ready reckoner.
Additional to the above would be your pension lump sum which is currently tax free.
There is provision to retire with an actuarially reduced pension at any age form 55 - based on your years served and then with an actuarial reduction applied. Alternatively you can resign and leave your pension undrawn until 68, avoiding the actuarial reduction.