Ang aking klase Aking Klase sa Tagalog  (always remember to use capital letters with your title)

PS.

I hope my corrections would help you more with your Filipino. If you have questions regarding my corrections or anything about Filipino language, you can ask me here anytime or in Skype. God bless you. 

I just entered this site, though if you wouldn't mind I would like to correct some things in your paragraph. Don't worry, you are already pretty good (one can technically understand your entry), just some minor issues. Hope I can help! 

Ang aking klase sa Tagalog

Just be careful in ending in ng but I guess you'll learn it later on. There were some that I removed but a little more polishing will do. Also the thing about the nang and ng, there are times when one should use nang instead of ng. Actually, a lot of people here don't use nang but for technicality it is for how (regarding how aspects). Kaya is That's why and Dahil is Becuase. 

To be honest, I myself am not a native speaker of Tagalog (I have another regional language (Bikol) as my mother-tongue,yet almost everyone here can speak or at least understand Tagalog. We have lots of languages here in the Philippines, well depending on who would be counting. Good luck and hope you'll appreciate and like Tagalog. 

Mula April nagaaral ako ng Tagalog sa isang kolehiyo sa Germany.

** Simula noong April, nag-aaral ako ng Tagalog sa isang paaralan sa Germany.

May isang programa sa Southeast Asia ang itong kolehiyo.

** May programa ang paaralang ito sa Southeast Asia.

Nalaman ako ang tungkol sa klaseng ito galing sa isang kaibigan ko.

**  Nalaman ko ang tungkol dito mula sa aking kaibigan / mula sa isa kong kaibigan.

Half-Pilipina, half-German siya.

** Siya ay kalahating Pilipino, kalahating German / Siya ay half Filipino, half German.

Meron mga tatlumpung estudyante sa aking klase.

**   Mayroong tatlumpung estudyante sa aking klase.

Ang karamihan ng estudyante ay half-Pilipino. Malamang 90 percent sa kanila.

**  Karamihan sa mga estudyante ay kalahating Pilipino, malamang nasa 90 porsiyento. 

Ang karamihan ng mga half-Pinoys hindi sila kayang magsalita ng Tagalog. Dahil nagaaral kami ng Tagalog sa isang klase.

** Karamihan sa mga half Pinoy ay hindi nagsasalita ng Tagalog, kaya kami nag-aaral ng Tagalog sa iisang klase.

Tatlong buwan tatagal ang klase sa Tagalog.

** Tatlong buwan ang itatagal ng klase.

Sana matututo ako marami sa Tagalog.

** Sana marami akong matutunan sa Tagalog.

This is my edited version.  You can compare it by sentences.  I rearrange your sentence construction by sentences so you can easily distinguish the difference.  Notice that I highlight with yellow the words that I changed, and with green for my corrections.

I hope this helps :) You can also check my profile :) Thanks.