Our estimated date of NOA2 was May 29th and we've got ours on May 4th. But you will not get a fair view by asking people this question, cause estimation fluctuates each month, depending on how many VJ-ers complete their timelines the previous months, or on the percentage of the VJ-ers from the total numbers of petitioners, of the number of applications itself in the previous months etc etc etc.
More fair it would be to estimate your NOA 2 at approx. 90 days from the date of your NOA1 (not the date you received it, but its issuance date). But I would not advise you to put all your hopes on such date, cause there are VJ-ers who waited far more long for their approvals...
Good luck on your journey, either way you're close to the first big step

, your approval.