Welcome to the madness that is violin, stephie.

Yes, most people do need a bit of time to "muscle up" in the wrists and hands.  It doesn't usually take long, though.  But even if you have strong hands and etc, the motions of playing are different than what your hands/arms/Do you get neck tension/shoulders/back will usually be used to. 

But if you start getting sore at all, back off a little and let your body get used to this stuff.  It is easier than people think (at any age) to get a bit of tendonitis or be over-extending a joint without really noticing it when you're concentrating on playing.  If you don't listen when your body gives you the warning signs, you can end up not being able to play for a few weeks, and that would suck.

Better at first to practice for shorter periods and work up to longer sessions than it is to risk injury or burn out from expecting too much from yourself at once.

Another thing to remember is that you do not have to do all of your practice/playing at once.  If 15 min now and 20 min later and a few min after that works out for you, that can be good.

I'm 54 yrs old and have been playing violin for 3 yrs.  I've been playing guitar for more than 10 times as long, though. 

What I find works well for me is an hour of what I think of as actual practice.  Meaning an hour of the stuff most folks find less fun at first like scales and exercises.  But then I play as much as I feel like for the rest of the day, whenever I like. 

An hour on an instrument all in one session might be too long when first starting out though, since you do need to let your fingers, hands and body get used to the activity and you will likely be using at least a few muscles you usually don't.  So at first, just try to make some time for that stuff.  Yes, it can feel like a bit of a chore, but scales and exercises are the quickest way to improve your overall playing.  At least as part of a "balanced diet".

Oh, and it really helps if you stretch and warm up your muscles a bit before playing.  Even 5 minutes of that before playing on any instrument, I have found to be time well spent.

Mostly though, let yourself be like a kid with a new toy.  Pick up the violin whenever you have a chance to play even just for a couple minutes, as often as you can.  Might be just one quick run through a verse of a song you just remembered or trying to do one "trick" you noticed when watching some more accomplished player on youtube or whatever.

Keep it fun.  Let yourself feel excited.  Dream.  Laugh when you goof up and just try again.  Make a game out of seeing what little thing you can do even a tiny bit better today.  This isn't a job, it is a love affair.  If you let it get to feeling like just a chore, and you can't feel the fun/joy anymore, and you can't get it back, then it is all over.

Ok, I'll get off the soapbox now.. LOL