mongoose find related documents

I am using mongo db and i have realized this wasn't the proper solution for my backend. I have two models that are related, let's call them Account and contact such that contact has a field called account_id. I am curious, how much of a performance impact will this be:

Contact.findOne({id : my_id }, function(err, aCon) {
    Account.findOne({id : aCon.account_id}, function(err, anAcc) {
        // some ops
    }
}

Is this issue enough to warrant switching to a new database layer? In my use case, I can't use the embedded doc method and I would like to avoid duplication... I think this is really the only solution