First of all,
Welcome Home to the Catholic Church! It's awesome that you are back.

Don't fret- if you pursue the religious life at this time, the communities will probably be welcoming, but encourage a healthy period of time "back" in the Church before any serious decisions can be made.
Your age, being an anullee, and having dept aren't strikes against you; however, they will narrow your discernment a bit (which may turn out to be something you are very grateful for! With the abundance of good communities these days, it is probably nice to have a few communities knocked off the list beforehand

) There are certain Orders which do not take anullees, but not many. As for your age, that could be a consideration for many communities, but exceptions are often made if the woman truly has a religious vocation. A side note on age, which you may hear from a number of communities, is that it is very difficult, generally, for women who have been in the world for a long time to adjust to the religious life and have the docility to transition since they are set in their ways (naturally!). This is, from what I have been told by several superiors, the reason many Orders do not take women past the age of 30 or 35. But, exceptions
can definitely be made; cases are usually examined on an individual basis. And as for dept, your "probation period" of time back in the Church (if there will indeed be one, as there is for converts), will probably give you time to take care of that. There are programs, if it is a large sum, which can help with those types of things as well.
As for discerning this call: Reception of Holy Communion and frequent visits to Jesus in the Blessed Sacrament (in Eucharistic adoration or just making visits to Jesus in the tabernacle at church), is the
best way to discern. Probably everyone on Phatmass would tell you that. Lectio Divina can also be a helpful tool (and it is often recommended by our Holy Father, Pope Benedict XVI).
Look around online and see if any communities draw your attention. There are two types of religious life for women: active and cloistered (contemplative). There are also some Orders which do both, active and contemplative. There's something called Vocations Placement which may be very beneficial for you:
http://www.vocationsplacement.org/Be assured of our prayers. You can send me a message if you'd like to talk further, and I'm sure there will be lots of other PM'ers with good advice to share! God bless!
In Jesus,
Lauren