Oh yeah, I should've been more precise. I blame the heat. What I meant was that it's usually easier to mobilize the youth instead of the elderly in the run-up to an election/vote. Hence why "enthusiasm" isn't necessarily a good indicator.
When it comes to the actual election, absolutely it's what you described. Elderly turnout is consistently higher than the youth's.
Any new deal would be a very different beast altogether, though. The proposal that is on vote today was for the extension of the second bailout program under the EFSF but that program expired on June 30. A new, third bailout program would be under the ESM as Tsipras and Varoufakis have said. However, one CDU MP said recently the contagion risk of a Greek default for other EU member states is low, thus a bailout under the ESM would not be legal. Question is, does he have a point? If so, what then? Also, the German Bundestag has to approve of new talks about a third bailout program before it can actually happen. Will they? There's a growing discontent in Merkel's CDU/CSU party.
Also, the third bailout program will likely be a much broader package than the 6-month extension for the second bailout program. Going by the IMF report, it may need to include a debt relief and/or a debt restructuring.
All these questions need to be answered. Had Tsipras signed the extension of the second bailout program, the Greek government and the institutions would have had six months to answer these. Now, they have until July 20, otherwise Greece defaults. That's why I echo what SymbiantXenos said: A new deal in 48 hours seems highly unlikely.