They're not dumb, better to ask now and get it right than to ask later.
My reasoning for suggesting a routine such as that above is, as well as the reasons you mention, but also because:
- It's simple, as a beginner the last thing you want to be doing is overcomplicating things;
- It comprises the basic compound lifts on which you should be learning perfect form to prevent you from getting into bad habits;
- It will hopefully lower chances of future injury as the high rep, low weight structure will ensure correct form is adhered to (which also bolsters the point above) since you won't be sacrificing form in an attempt to chase higher numbers.
Ultimately it's completely up to you when you decide to change routine. Don't be fooled into thinking changing every few weeks will "confuse" your muscles into growing and boost hypertrophy yadda yadda. Muscles can't get confused. Different movements that target the same muscle group can place more emphasis on different muscles within that group, however. For example: seated calf raise and standing calf raise; chin ups, pull ups and BORs; lateral and front dumbbell raises; etc.
Maybe after a couple of months of the above it would be worth experimenting (by all means experiment from the beginning, but it's important to have quite a rigid base routine to stick to as consistency is key). Perhaps try a Stronglifts 5x5, that was my first experience of weight training and I really enjoyed it, though I did modify the routine somewhat. You could try a bodypart split (push/pull/legs) to see how you like it, you might find you love smashing your chest with 3 or 4 different exercises on one day, likewise back and legs on their respective days.
I'm currently on a 3 day split, however after 3 days my muscles feel perfectly fine again. Is it detrimental to train a muscle more than once a week? I'm really tempted to do biceps & triceps every 3 days instead of once every 7 days. Is this a good idea or would this only hurt my progress?
I wouldn't do bicep/tricep specific exercises full stop let alone multiple times a week, completely unnecessary unless you're an advanced lifter. By all means hit them multiple times per week as subsidiary muscles when doing compound lifts, but targeting them specifically is a waste of time unless you have very good reason.