Many a mistake has been made (and lots of time wasted) by trying to download an 'improved' version of something that you find perfectly useable for your needs. You'll need a pretty new spec computer to run XP too (or, come to that, Win2000 or anything else after 98SE). If you're happy using 98SE, I would say stick with it.
I had an old laptop with Win 98 that was an upgrade from Win 95. Over the four years that I had this computer the OS became more and more unstable but perhaps I should have reformatted and re-loaded the OS. Anyway I have now bought a new computer with a spec. that would allow the demands of Win XP and am finding it very good, so far that is until it......................................OH dear!!!
98se is an excellent operating system, I used it for just over two years, no problems at all, I have put the CD on one side for future use if required. Don't worry about support being withdrawn, this will not affect the O/S in any way, it will carry on working as well as it does now.
I up-graded to XP Pro. mainly because I liked the look of the interface, this O/S also works perfect. Unless you have a need/wish to use XP. [ The best O/S yet, "I think".] Then you can carry on using 98se until you cannot find any hardware/software to work with it. This will be many years yet, and we may all be using different equipment then, than we use at present . Regards. j.