I literally just made an account 60 seconds ago and I don't know what I'm doing. I hope I'm in the right thread and not breaking any rules.

So, I'm a new Sherlocker. I just finished the series and am now, like any good fangirl, am writing a fanfiction. I'm really excited about the plot I have formulated and have high hopes for the fic. HOWEVER, I have a problem that is quite detrimental. My fanfiction takes place during "His Last Vow" after Sherlock confronts Mary Watson in the facade. I won't bore you with plot, but essentially Sherlock and John end up as bachelors with Mary and John's baby, but no Mary. My fanfiction then takes off from there and basically depicts Sherlock and Watson having to raise this baby themselves. Thus leads us to my major dilemma. 

How do I write a story surrounding a baby who hasn't even been named in the series? All we know about Baby Watson is that it's most likely a female. That's literally it.

So my struggle is, do I just name the baby myself? Make up a name that obviously won't be cannon in the series? And the even bigger question, WHAT do I name her? 

Anyways, that's my problem that's losing me my beauty sleep. I'd be overly appreciative of any opinions and/or suggestions. THANK YOU!