I’d advise you to take a few lessons with a DB tutor as most starters I have seen don’t naturally develop correct left hand technique (if you’re right handed). You should get more from that than you’d believe, including holding the bass. If you sit, as I do, invest in a good adjustable seat.
Consider an adjustable bridge, it doesn’t look like yours is. That allows you to lower the action when you start out which eases the effort required(at the sacrifice of unamped volume).
Finally, as has previously been said, play for short periods at the start. Injury is bad news.
Good luck.