Alexandra,
The Deutsches Museum is massive (16 kM of exhibits at the main site), so I'm not sure that a guided tour would really be worthwhile. In any case, it appears that they only offer German-language tours for small groups.
I've found that it's better just to get the printed guide and wander around on my own to see those exhibits that interest me. The exhibits are all labelled or at least easy to understand. With a self-guided tour, I can stop for a break, a coffee or meal when necessary, rather than being herded around with a group. I can't recall whether they offer Audioguides, but I suspect those will be available.
The exhibits I found most interesting may be different than what you would find interesting. I like technology, so quite enjoyed the computer section, electrical section, astronomy section and Amateur Radio sections. I'm also interested in WW-II history so enjoyed seeing hardware from that era.
Happy travels!