I miss my baby face! I am almost 28 and used to have a full baby face but it is gone now. (Photos)

The wonderful thing about hyaluronic-acid based fillers like Voluma is that if you want to add more, you can. It’s best to be a bit conservative when first using fillers, so your injector made the right choice to take the slow approach. 
However, you are quite youthful and beautiful looking already, so be sure that you are making this change for yourself, not to win your boyfriend’s approval. Aging is inevitable; to some degree we all have to accept it. You can look beautiful and radiant and attractive at any age if you take care of your skin and help resolve the issues that most  trouble you (not someone else). Be sure to consult a board-certified dermatologist who makes you feel confident, is willing to work with you over the long term to keep your skin looking gorgeous and healthy through the coming decades, and who is an expert at rejuvenating the face with Voluma.

Both implants and fillers in the cheeks and/or chin can create good results for patients. Both can build up the face and create symmetry. You must balance the pros and cons of each procedure and do what you feel is the best decision for you.
Fillers:
Pros: No downtime Reversible Quick
Cons: Temporary More expensive in long run
Implants Pros: Permanent Great for patients with poor bone structure Less expensive overtime
Negative: Risks associated with surgery Possible infection Downtime
Hope this helps.

You still have a baby face and are very pretty. You can have some fat injection in some parts of your face and the stem cells in the fat will retain the youthful appearance for you. Voluma has the be repeated and considering your age it is going to be costly to keep getting the injections.