Hi Bobby,
When it comes to films, there is so much choice that you'll get conflicting recommendations on the boards. Honestly, you won't find any of the Big 3's (Ilford, Kodak, Fuji) films wanting for quality control or consistency. That's also true of older Agfa stocks that are still being sold. I've never used them, but i understand, as pointed out above, the smaller European firms don't match up quality-wise.
Generally speaking, faster films yield coarser grain, which you'll notice on 35mm enlargements.
The higher the ISO / ASA Number, the more sensitive to light the film is.
With a more sensitive 'fast' film, say 400 ISO and above, you'll need less exposure, meaning a faster shutter speed and / or a narrower aperture. You can hand-hold the camera at lower light levels and still have reasonable depth of field without getting subject blur.
With slower, ie less light-sensitive films (under 400 ISO) you'll need more exposure, meaning slower shutter speed and / or wider aperture. In lower light, hand-held images will be more susceptible to subject blur or hand-shake blur. Depending on the results you want, you might need a tripod.
For outdoor use, you could try a slower (100-ish ISO) film and see how results differ. Do you have a tripod? Try using a slow film for the balloon glow, with multi-second exposure at a narrow aperture. Alternatively, push the Tri-X to 1600 and hand-hold the camera. I've done that and had good results in low light. If you buy 1600 ISO film, you could push that to 3200 ISO.
There are also the mono C-41 films like Ilford's XP-2 Super (400 ISO) and Kodak and Fuji's equivalents. These are very flexible films based on colour film technology; you can over- or under- expose and still get decent negatives. they can be processed at any mini-lab and you'll get proof prints, the downside is a loss of control over the processing.
Don't be afraid to experiment with different films and techniques. Also, don't be afraid to make 'mistakes'; that's how we learn. Use the internet, books and magazines to research things like film speed, film choice and other issues you might come across. Also, there are lots of helpful threads here on APUG. But there's nothing like personal experience to teach you, so take pictures and have fun, IMO.