They are pretty unlikely to get heavy on you and call you anything like weak or apostate as you are not baptised. You are still in that category of person where they need to keep their smiley faces on and to 'give a good witness' by their behaviour, so that they don't put you off! LOL bit late for that now...
I think you are wise though to 'suck it and see' * , if you don't feel adequately prepared to combat the doctrine, then don't, just make your excuses and then do any research you need to at your own pace and in your own time. Nothing worse than having to learn all about something in order to prove it is a load of nonsense. Bit like the Trinity brochure ^^ (no offence trinitarians!)
Even so, it's clear you want to have a real go at them, so you damn well go for it! And your point is certainly valid, remind them of some of the many altered doctrines and failed prophecies, it will at least make them think, as that stuff is almost never referred to again once it has been changed.
And as someone who wants to continue worshipping God, you could always refer to how they have been actively discouraged from reading and discussing the Bible in groups outside of meetings and without WT literature. Which for any Christian is a shocking thing to demand, to not be allowed to read God's word by itself and discuss it with other believers.
( * lol reminded me of an assembly rehearsal once where a brother used that expression, and the C.O. afterwards gently said "oh and by the way... 'suck it and see'... any chance we could have 'play it by ear' instead?" :D)