Ajeng, welome to Bigger Pockets =)
Baltimore is a great place to invest in, but you need to know the area well. Some people on this forum have asked, "What zip code should I invest in?" and the correct response is: "Bad question! You need to get way more granular than that!" Even "what neighborhood should I invest in?" is not specific enough some times. Your criteria for looking near colleges and hospitals is generally a good idea, but that thinking is too broad. For instance, Johns Hopkins Hospital, one the most renowned hospitals in the world, is an oasis of sorts. This premier hospital, with tons of money, is surrounded by neighborhoods I would not want to invest in (excluding South - South of the hospital is solid).
Your questions about investing near colleges - they typically come with their own challenges (solid demand, but frequent turnover, etc). I have no idea what the pandemic is going to do to the college market - your guess is as good as mine. Same goes for waiting after the pandemic to invest. A lot of people on Bigger Pockets are saying that it's not a bad time to buy, but it's hard to find good deals (i.e. if you find a good deal - go for it!). Personally, since I'm looking for my first deal, I've decided to wait until the Spring this year and use the next few months to get all the pieces in place while analyzing deals on a regular basis. It's not the right choice, it's just my choice.
Also, Baltimore County is a different ballgame than Baltimore City. The county does has a lower price-to-rent ratio, lower taxes, and more competition.
At your price point, you wouldn't be able to get a 3 bedroom SFH in an A neighborhood (most of the ones by the waterfront, for example), but you could find something in a B neighborhood. Maybe try Pigtown, Joseph Lee, Greektown (near Bayview). But take that with a grain of salt - I have lived in Baltimore, not invested in Baltimore yet.
Hope this helps =)