Next year I have to go to university. I am very worried about this. How will my new classmates perceive me, will there be time for my passion for hobbits, and in general, is it worth talking about this in a new educational institution?

Congratulations on getting into Uni!

I expect you'll have a lot on your plate during your time there between studies and socializing. You shouldn't have trouble setting aside some time for hobbying and playing if time is managed well. It's good to have something quite, like painting, to fall back to sometimes.

The real trouble I ran into was dragging all my supplies and models around with me and then setting up a space for it. I hauled a bunch of stuff with me at first only to never use most of it. I recommend only taking a small set of stuff for playing and a single painting project that you can chip away at over the semester. And maybe hold of on taking any army to play at all the first semester until you get a feel for the area and see if there is anyone to actual play with.

As for talking to other people about your hobby, most people will probably not give you any grief about it. Public opinion isn't what it was 20 years ago so you don't need to be worried about being mocked or shunned unless wargaming is all you ever try to talk about. In my experience, people show a passing interest and then are ready to move the conversation along because they aren't willing to get bogged down in what is plainly a complex subject; same with books really. I won't be worried about mentioning it briefly if you are asked about your interests. Also, keep your eyes peeled for gaming clubs. Might be some similarly interested people kicking around there.

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"Draw your sword with a heavy heart, but swing it with a heavy hand"

It is slightly more than half a century since I was at university, our children were at uni much more recently! When our children were at uni (in UK) they were able to wargame at a local club and also at a Uni Society. Even when I was at uni we had a large number of societies that played wargames and even the the new and rather strange, innovative game called Dungeons and Dragons! I remember discussions about Tolkien, adapting D&D for Middle Earth and lots of historical wargaming ideas. But, as already said, don't swamp your listeners. Many will be interested and some intrigued enough to try a game so if you have the boxed set and the basic rules take that with you.

In the UK most universities run a Freshers' Fair at which the societies do their best to recruit so you may find something there.

As far as actually building and painting is concerned there should be time for you to indulge. Follow the sage advice already given about having only a single (small) project. You can always adjust the amount once you have an idea about balancing study, lectures, socialising, sport, hobbies, (part time work for extra cash?) and so on.

Enjoy your time and best wishes.