Do any of you journal?

I have 1 friend but we don't see each other often and we speak a few times a week but not enough to talk life problems over with. I have a fiance too, we've been together 7 years with 2 children to whom I'm a SAHM too. They are 3 and 18 months. My fiance works full time 6 days a week. I can't talk to my mum she's not great for advice she thinks her was is the right way and if I try to suggest other ideas or challenge her opinions she's shuts down and changes the subject. I'm close with my sister but she's only 16 and theres things she doesnt need to know and I don't want to burden her with my issues. There's a lot going on in my life. I'm 21. Still so young and I'm trying to get my life together bit by bit but it's hard having 2 young kids and now things have become even more uncertain with all this covid stuff. I'm doing online schooling to get a childcare qualification. So I've been thinking about starting a journal. To write down my days and any feelings I may have about anything just to get it out. Ita been eating me up and it's affecting my mood, my patience with the kids and my partner, my attitude and they way I view life. I'm just not happy in myself and I feel if I write it down my partner can read it if I feel like I can't say it to him. Does this sound like a good idea?