hi Diane and welcome.
Based on my own experience, I'd say hybrids are a very good choice for a first-time keeper of just a few garden hens. They come in a big variety of breeds, shapes and sizes, so you can collect a diverse flock which look interesting in the garden and you can tell them apart easily. They are all bred to be naturally tame and friendly, ie to tolerate confinement or life in a large commercial flock, though of course the lucky ones, like yours and mine, get a much better life than that. They produce eggs reliably because that is what they have been bred to do, and they don't waste time going broody and having to recover from it for weeks on end, like many purebreds, and this is important to most first-time keepers of a few hens. They will have been vaccinated against most of the common chicken diseases, and although this won't guarantee healthy hens, in most cases it does help, especially a new keeper. Some people on here have had unfortunate experiences with vaccinated hens, or with mixing vaccinated with unvaccinated, but i have never found this a problem and my 2 hybrids live healthy happy lives with my Buff Sussex and Cream Legbar. In my experience, hybrids kept under domestic conditions and not pushed to lay with extra lighting in winter, will lay reliably but won't be put under such pressure as in a commercial setup, and so should go on longer and lead healthier lives, though as Chris says it may be that they reach the end sooner than some purebreds. However, 2-3 years is a good length of time for a new keeper to find out more about chicken keeping, perhaps visit poultry shows and exchange experiences, before committing to a particular breed by finding out through practical experience what exactly they want their hens to do and provide by way of performance.
If you do decide to get some purebreds, and eggs are at all important to you, do enquire very closely about whether the birds come from a utility egglaying strain, or are being basically bred for frilly knickers or topknots and appearance. The ones you will be offered will in all likelihood be 'show rejects' from a breeder who is quite legitimately selling 'pet grade' birds and keeping the best for his own breeding line. If the hens are healthy there is nothing wrong with that, and if you aren't going to show it doesn't matter if the birds don't match the breed standard. But if you want eggs, be aware that many breeds look pretty at the expense of laying performance, even what you would think of as standard utility breeds such as Sussex.
Another factor is when you want to buy your birds. the best age is at point of lay (POL) which means in practice anything from 16 to 24 weeks, as most pullets start to lay around 22-24 weeks, with exceptions either way, from 18 weeks to over 30 in some purebred breeds. This is also affected by the time of year, with birds coming towards lay in the autumn taking longer than those maturing in Spring. If possible, 16 weeks is a good age to get your birds, as although you'll have to wait for the first eggs, the birds have time to settle in and grow on until that first exciting egg appears. Hybrids are usually available at POL throughout the year, being raised mostly under commercial conditions with extra lighting in winter if needed, so you could get these from now onwards. Purebreds wiil be hatched in January-March, and so won't be at POL until July-August, so if you want these you'll have to wait until then. One possibility is to buy chicks or growers now, and raise them yourself, which is what i did with my 2 purebreds. I chose those 2 breeds because they are autosexing/sexlinked, so i could get 5-week-old chicks in the knowledge that they would be pullets and wouldn't start to crow! I really enjoyed raising them and they became very tame and have great personalites. Also I had their company for the months that otherwise they would have been in a bigger flock at the breeders, and of course as chicks they cost much less than they would have at POL.
Chicken collecting is addictive, so it's a good idea to get fewer than you have room for, and to get a larger coop than you need at first, leaving space for additions perhaps in the next season. Bear in mind that they'll need a minimum of 2 sq. metres of run space per bird, and that more than this is desirable to prevent stress and fighting and feather pecking etc, so have a very clear idea of the limits of your potential flock before you start. When you do decide to increase the flock, it's always good to get at least two at a time as it makes integration much easier than with a single bird who will be mercilessly bullied by the existing flock.
Good luck and do let us know how you get on.