A few words of advice
1. a drysuit keeps you dry but you will need additional clothing to keep you warm (-->dress according to weather)
2. neoprene drysuits may be slightly warmer, at least near the surface (not compressed) but they are stiffer than trilaminate suits. Personally, i prefer the latter but that's just me. Oh, yes, there are rubber suits, too.
3. in either case you will need
technical undergarments and a warm coverall; technical long johns & long sleeved shirt to give you a dry feeling and woolen socks and a warm coverall to keep you warm...
Buy these first
4. contact
local drysuit divers to learn how much clothing you need to wear under the drysuit
5. put your undergarments on and try the drysuit on
6. you need to be able to sit on your knees comfortably and to
touch your back behind your neck. If you cannot, the suit is too small
7. if the legs are too long, you can fold them and use gaitors - a suboptimal solution, which I use all the time (because of money of course)
8. drysuits are expensive but they should last a couple hundred dives (400+) if treated well and
serviced regularly. Latex seals need occasional replacement as do zippers. There are legacy zipper-free options in rubber (jacket & trousers rolled watertight) in case you feel more like the historic diver (it's a thing, too, you know).
9. drysuits come either with a fixed hood (which I prefer because they leak less) and no hood at all (comfy in hot weather; don one once ready to dive; this is what I unfortunately got). Both altenatives are good. This is strictly a personal preference thing.
10. Gloves - the epic battle. Some of us use five finger gloves (me), others (me again) prefer three finger gloves, and still others (me) wear dry gloves. Wet gloves are easy, comfy, nice. The three finger version (1+1+3) is warmer and just as dexterous (when did you last time use those thee little fngers and which one is better: three warm or five cold?). Dry gloves are equally warm at ANY depth. They also always leak and it sucks (they are valuable for longer deeper dives in very cold water). Anyway, you will end up owning all of these plus a few hoods and a pair of fins. You can never own too many hats, gloves and shoes