I’d get one now or wait. It’s highly unlikely there will be a super, and even then it won’t be much if any different to the original apart from price. The Ti is over a year old at this point so next gen is likely to be coming very soon.
I was taking a look back through Geforce desktop card releases (using the highly reliable web source that is Wikipedia), to get an idea of timescales for release. They were pretty much annually, at the top tier, save for a couple of examples. top tier card prices were fairly stable too for a few years. I've given the top tier card (non Ti, Titan or double card PCB, basically the XX80) price as an example.
400 Series - March 2010 - $499
500 Series - March 2011 (570 and 580 followed in Nov/Dec) - $499
600 Series - March to May 2012 - $500
700 Series - May 2013 (Ti in Nov) - $499
900 Series - Sept 2014 (Ti in June 2015) - $549
1000 Series - March to May 2016 - $699
2000 Series - Sept 2018 - $699
Its hard to compare Ti prices as at the top tier they dont go back too far, with the x90 double card PCBs were on offer (basically 2 GPUs on one chipset) but from 780Ti up to 2080Ti it goes something like this:
$699 > $649 > $699 > $999 / $1199 (Marketed as founders ed.)
My point is that, irrespective of whether Ti variants are rolled out simultaneously as their x80 counterpart, there has never really been more than 18 months between iterations. On this basis Q1 to Q2 seems a reasonable assumption for 30XX? series.