I'm 18 about to be 19 with $7,035.45 in the bank and around $10,000 in assets, should I start investing now?

I work for Walmart, I make $14.14/hr and I'm about to become a TL and make $18.14/hr. I live with my parents and the current plan is staying with then till I'm 22, I pay $300 a month for rent (they said they won't increase it) I also pay my insurance which is $75 + $35 for phone + $60 for gas. So around $475 a month. I make a total of $1,836.20 - $475 = $1361.20. Now what I want to do put $400ish a month into Walmart stock (they match 15%) and $100 into 401k (they match 6%). Would this be a good choice? Right now I'm set to make $24,000 this year, I don't really go out much, and if I do I'm normally just hanging out with friends (we rarely spend money) and just do stuff that's free 90% of the time.