Am I the only one who could not understand the word "hemden" at all when it was said?
try this: mein = my/mine (masculine or neuter nouns) meine = my/mine (feminine or plural nouns) Hemden is plural, therefore 'Meine.'
Nope :) As far as I'm aware the "scharfes S" is slowly becoming extinct. Fingers crossed that the umlauts follow eh? :p.
Weiß is a good example of that, with Weiss being used more and more frequently (probably because of us auslanders ;p). However, bear in mind that "weis" doesn't mean "white".
In Switzerland they don't use ß so for them it's not wrong. Also, if your keyboard doesn't have it you can use "ss" instead. You should however try to use in every case or else you will develop bad habits (since you are still new to German).
"meine" is feminine and plural. "mein" is masculine - it's a der, die, das thing. "Hemden" is plural (shirts) so we need to decline the article (Verbs are conjugated; nouns and adjectives are declined).
Once you've got the bit worked out (which I think I have) you then need to work out which case (accusative, nominative, genitive, dative) as that also influences the declination....
German...it's fun...so I'm told ;p