Welcome!
As everyone's said, rent first. By the time your UKARA's sorted you'll know whether it's for you or not and will have probably had a go on some other people toys so will also have a much better idea of what you want. You'll lose plenty of money if you buy a two-tone and then decide you don't like being shot at, or buying an M4 and then realising you'd rather an AK.
Research stuff and ask questions, there's plenty of knowledgeable folk about and we really don't mind passing that on - use the search function first though as sometimes we're a grumpy bunch and you may find the first answer is along those lines with a link to the relevant thread.
Decide on your budget too, it's very easy to become very poor in this game because we're all essentially the airsoft equivalent of magpies trying to hoard pews, n+1 and all that. Mags, batteries, chargers, gas, scopes, grip, sling, chest rig, boots, eyepro, facepro etc etc all cost money and there's no point blowing your wad on a pew if you can't use it for a few months because you can't afford mags - unless that's your plan of course. Me, I'm not that patient!
If you really think you're in it for the long haul and want to scratch that itch and buy stuff than I'd recommend getting non-shooty things that'll help as a rental - you may not like the rental PPE so eye & face protection would be sensible, as would a pair of boots and gloves.