You don't mention if you've had a root canal on the tooth before, and if so,
a crown on a front tooth is usually the best option.  If you haven't had a
root canal, be sure the dentist checks the vitality of the tooth prior to
restoration given you said the tooth looks darker now.

Assuming the tooth has not had (and will not need a root canal), restoration
with a crown or veneer depends on how much natural tooth structure is left.
With lesser tooth structure available, a crown is recommended.  However, if
enough of your natural tooth struture remains, many times a porcelain veneer
can be made.

As for all porcelain vs porcelain/metal crown, certainly there is better
esthetics from the all porcelain crowns.  However, your particular bite may
prevent the dentist from using all porcelain.  Talk to your dentist.

John

Hi:
        In most cases for a 27 yrs old female...You demand high
cosmetic result. You need to see a true cosmetic dentist who know what
they are doing. They will tell you after a detail exam what is your
best options.....Typically you want all porcelain crown or venneer( if
it is possible).....This is what we do in our office
1. Complete exam----discussed options, patient desires and expectation
2. Case work up ( For additional Fee)- Diagnostic photos, Mounted
Models, Wax up, Photo shop pictures- This will give us and the patient
best idea what is available and clear picture on what result patient
will get when the treatment is completed.
3. Actual treatment- Once patient decided the option he/she want and
agree to the fee. we will start
4. Try in-Prior to cementation- Minor adjustment may be needed
5. Cement of restoration and schedule for recall

I told all my patients....Rome was not built in one day. It is easy to
do 6 crown for your front teeth, but it is difficult to maske one
crown to fit all your teeth. Don't you want to know what it will look
like before you spent any money and have the crown make? So find
someone who really know what they are doing, and who can do it well.
You won't regrate the money you spent.
Best wishes........Albert

Can you post some pictures and x-rays ?

For front teeth I tend to go all porcelain, and depending
on remaining tooth structure either veneer or mini-crown.