Does Eros confirm the providers are of legal age?

I think that there are two levels of Eros ads these days: The regular old ads (lots of fakes) and the new Premium ads.  From comments posted to TER, I think that they do require various forms of proof before they will post the ad to the Premium (Confirmed) session

......To get listed in this category, a lady must submit govermnment id, confirmed photos with a written sign showing the current date, that match her photos on Eros.  The other option, is to have met with representitives from Eros, at one of their marketing sessions. The ladies will have a red seal on their thumbnail.

make her send a copy of her ID confirming that she's at least 18.

...forward id, no matter the age.  Like you, I simply check the "Are you over 40" box, when paying for my ads.

If you think there is the slightest chance she might be underage you would be wise to move on to someone you're more sure of.

When posting an ad on Eros, one has to check whether they are over or under 25. If one is under 25, and Eros thinks they appear too young, they will require photo ID to confirm the lady is over 18. To verify one is over 18, you must send in a color photo ID, with the name and birth date clearly visible, and another picture taken yourself, holding a sign with the date, your phone #, and provider name, and that picture must resemble the picture ID(this is also how they do photo authentication on their site). If a lady checks that she is over 25, they still may request photo ID if they think she appears too young.