Hi hoping. I had my first round of IVF at age 39 and was lucky to have success first try. Two years later and the frosty from that round didn't stick, so had a second EC (just after 42nd birthday). I can't remember how many follicles I had, not many, but I did have one big one. They ended up collecting 2 eggs, but only 1 made it to blastocyst stage. But that one stuck and is due in Feb.
I was on 450 Gonal F, but nothing else. I can't remember whether I had ovarian twinges or not. They may pick up more follicles in your second scan, but they will probably be quite small. The 3 that have already been detected are your best bet - ask your sonographer what size they are and what that indicates.
Are you too old at 42? Well it worked for me! Not that that is a guarantee of anything, but you aren't ever going to be any younger than you are now, so there's no time like the present. Do you have a chance with only 3 follicles? Again, it worked for me - you only need one good one, and especially if you have a big follicle, there is a chance. Do you know the cause of your infertility? Is it just age (as it was for me, plus knackered tubes)? If you have no problems with your uterus, like endometriosis, etc, then yes, there is a chance. Be positive, but be realistic too.
There has been another recent thread on here about chances of IVF working at 40+, so have a look at that too.