Need to gain weight

trescape

Hey guys,

I've been trying to gain some muscle for the past 3 months. I started lifting weights bc I found out I was underweight.
I'm 50 kg (110 lbs), 1.68 m (5 '6) and my age is 18. Gaining weight isn't the easiest thing to do and I seem to be having a hard time doing so. MFP is telling me to eat 1920 calories per day but I still don't seem to be putting on weight.. I sometimes even find myself losing some. Is there something I'm not getting or doing right? I try to eat lots of carbohydrates and protein.
Also, even though I only got a little layer of fat on my muscles, I would like to work it off. Its not a priority right now but in the end I would like to lower my fat. I was curious if I should even try to lose it now since my bmi is so low. Is it even possible to gain muscle and lose fat at the same time? I've been reading articles about it but I'm not really feeling it. The more I read the more I feel like this is rocket science lol. Anyway. When would be the right time for me to start adding some more cardio into my routine and to create a little calorie deficit?

If someone could help me with the gains it would already help me a lot for now.

Thanks for reading!