Going against the grain, as someone who lost my mum fairly young (I was 22) to alcoholism after a very harrowing but short (two year) battle: yes, this is a problem, and although there's a possibility it will turn out okay in the long run, there's also the possibility of you developing a drinking problem and ending up in a far worse place than you are right now.
My own mum started drinking to cope with the grief of losing her father and within two years she was dead.
Grief is a long, long road: a few months in I was barely out of shock and it took until six months I'd say before I even started to properly grieve, then another two years until I started to feel anything close to normal and happy again. Everyone's journey through grief is different of course, but it's unlikely you will feel better a couple months from now, it might in fact get worse before it gets better, so what's the plan? To use alcohol to cope for potentially months of years? What about when you need more to feel the effects, and are hungover the next day?
For me, I found trying to avoid the pain was simply impossible so I found my own ways of coping with it: by actually embracing the grief, as weird as that sounds. Not being afraid of it. I would put on either my own music I listened to that made me feel less alone and spoke to what I was going through, or the music we shared together, and just lay in bed and let myself cry. Sometimes I would cry so hard I remember feeling as if my insides were going to fall out. And eventually, after however long it took, the tears dried up for a bit and I could get up, go make a drink, message a friend, do something else, until the next wave hit. I found by embracing it I actually felt relief because I felt closer to her, even though she was dead it made me feel like we were still connected somehow, like she existed. That raw, intense pain was almost refreshing in a way like jumping into a cold shower.
Getting out helped. Going for walks. Memories, looking at her photos and handwriting. Talking to loved ones who understood me and would listen and be empathetic. Ringing Samaritans to just talk about her. Focusing on doing other things even if I didn't feel like it like volunteering, going to work, hobbies, even if it was just going through the motions.
I think the very fact you're asking if it's a problem shows that you know it is: while that might be an amount and frequency of alcohol intake that resonates with others, using it as a tool to numb yourself becomes very seductive and hard to not keep returning to, especially if it works at the time, but this isn't a short term pain you're using it to cope with, it's a long term one that you must find ways to adjust to that won't ultimately make your life much worse.
I'm sorry if I sound harsh, I have so much empathy for you and I am deeply sorry you lost your mum. I hope that you find a way through it, but I can't sugarcoat that if drinking is the solution there's a possibility that you might be heading down a very difficult road. There are other ways to cope with grief. Manage your expectations, you're not going to be able to feel good just a few months after you've lost her. It's just about getting through the day. But alcohol is especially worrisome as it can start to feel like the easiest/only solution and then it becomes hard to not resort to it daily and so forth. Best wishes to you.